921872640 has 288 divisors, whose sum is σ = 3234752640. Its totient is φ = 222363648.

The previous prime is 921872629. The next prime is 921872759. The reversal of 921872640 is 46278129.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2945124 + ... + 2945436.

It is an arithmetic number, because the mean of its divisors is an integer number (11231780).

Almost surely, 2^921872640 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 921872640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1617376320).

921872640 is an abundant number, since it is smaller than the sum of its proper divisors (2312880000).

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

921872640 is a wasteful number, since it uses less digits than its factorization.

921872640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409 (or 395 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 921872640 is about 30362.3556398380. The cubic root of 921872640 is about 973.2482734617.

The spelling of 921872640 in words is "nine hundred twenty-one million, eight hundred seventy-two thousand, six hundred forty".