1538723920 has 80 divisors (see below), whose sum is σ = 3747795840. Its totient is φ = 586409472.

The previous prime is 1538723909. The next prime is 1538723933. The reversal of 1538723920 is 293278351.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 508171 + ... + 511189.

It is an arithmetic number, because the mean of its divisors is an integer number (46847448).

Almost surely, 2^1538723920 is an apocalyptic number.

1538723920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1538723920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1873897920).

1538723920 is an abundant number, since it is smaller than the sum of its proper divisors (2209071920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1538723920 is a wasteful number, since it uses less digits than its factorization.

With its successor (1538723921) it forms a Ruth-Aaron pair, since the sum of their distinct prime factors is the same (3326).

With its successor (1538723921) it forms an eRAP, since the sums of their prime factors are consecutive (3332 and 3333).

1538723920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3332 (or 3326 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 1538723920 is about 39226.5716065016. The cubic root of 1538723920 is about 1154.4812972952.

The spelling of 1538723920 in words is "one billion, five hundred thirty-eight million, seven hundred twenty-three thousand, nine hundred twenty".