21491959830 has 32 divisors (see below), whose sum is σ = 56269859328. Its totient is φ = 5210172000.

The previous prime is 21491959829. The next prime is 21491959831. The reversal of 21491959830 is 3895919412.

It is an interprime number because it is at equal distance from previous prime (21491959829) and next prime (21491959831).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21491959831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32563246 + ... + 32563905.

It is an arithmetic number, because the mean of its divisors is an integer number (1758433104).

Almost surely, 2^21491959830 is an apocalyptic number.

21491959830 is an abundant number, since it is smaller than the sum of its proper divisors (34777899498).

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

21491959830 is a wasteful number, since it uses less digits than its factorization.

21491959830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65127172.

The product of its (nonzero) digits is 699840, while the sum is 51.

The spelling of 21491959830 in words is "twenty-one billion, four hundred ninety-one million, nine hundred fifty-nine thousand, eight hundred thirty".