1646172920 has 128 divisors (see below), whose sum is σ = 4576780800. Its totient is φ = 520183296.

The previous prime is 1646172889. The next prime is 1646172937. The reversal of 1646172920 is 292716461.

It is a Harshad number since it is a multiple of its sum of digits (38).

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, 192659 + ... + 201021.

It is an arithmetic number, because the mean of its divisors is an integer number (35756100).

Almost surely, 2^1646172920 is an apocalyptic number.

1646172920 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 1646172920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2288390400).

1646172920 is an abundant number, since it is smaller than the sum of its proper divisors (2930607880).

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

1646172920 is a wasteful number, since it uses less digits than its factorization.

1646172920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8437 (or 8433 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 1646172920 is about 40573.0565769945. The cubic root of 1646172920 is about 1180.7514413159.

The spelling of 1646172920 in words is "one billion, six hundred forty-six million, one hundred seventy-two thousand, nine hundred twenty".