1538323644 has 96 divisors (see below), whose sum is σ = 4226148864. Its totient is φ = 429361920.

The previous prime is 1538323637. The next prime is 1538323663. The reversal of 1538323644 is 4463238351.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1257217 + ... + 1258439.

It is an arithmetic number, because the mean of its divisors is an integer number (44022384).

Almost surely, 2^1538323644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1538323644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2113074432).

1538323644 is an abundant number, since it is smaller than the sum of its proper divisors (2687825220).

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

1538323644 is a wasteful number, since it uses less digits than its factorization.

1538323644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1987 (or 1985 counting only the distinct ones).

The product of its digits is 207360, while the sum is 39.

The square root of 1538323644 is about 39221.4691718707. The cubic root of 1538323644 is about 1154.3811816028.

The spelling of 1538323644 in words is "one billion, five hundred thirty-eight million, three hundred twenty-three thousand, six hundred forty-four".