921457821840 has 160 divisors (see below), whose sum is σ = 2864801212416. Its totient is φ = 245010501120.

The previous prime is 921457821839. The next prime is 921457821841. The reversal of 921457821840 is 48128754129.

It is an interprime number because it is at equal distance from previous prime (921457821839) and next prime (921457821841).

It is not an unprimeable number, because it can be changed into a prime (921457821841) 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, 225238195 + ... + 225242285.

Almost surely, 2^921457821840 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 921457821840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1432400606208).

921457821840 is an abundant number, since it is smaller than the sum of its proper divisors (1943343390576).

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

921457821840 is a wasteful number, since it uses less digits than its factorization.

921457821840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6597 (or 6591 counting only the distinct ones).

The product of its (nonzero) digits is 1290240, while the sum is 51.

The spelling of 921457821840 in words is "nine hundred twenty-one billion, four hundred fifty-seven million, eight hundred twenty-one thousand, eight hundred forty".