921997648 has 160 divisors (see below), whose sum is σ = 2239856640. Its totient is φ = 361428480.

The previous prime is 921997631. The next prime is 921997649. The reversal of 921997648 is 846799129.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921997649) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5520861 + ... + 5521027.

It is an arithmetic number, because the mean of its divisors is an integer number (13999104).

Almost surely, 2^921997648 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 921997648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1119928320).

921997648 is an abundant number, since it is smaller than the sum of its proper divisors (1317858992).

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

921997648 is a wasteful number, since it uses less digits than its factorization.

921997648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345 (or 339 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 55.

The square root of 921997648 is about 30364.4141718558. The cubic root of 921997648 is about 973.2922630238.

The spelling of 921997648 in words is "nine hundred twenty-one million, nine hundred ninety-seven thousand, six hundred forty-eight".