21494657408 has 64 divisors (see below), whose sum is σ = 49528523520. Its totient is φ = 9100976640.

The previous prime is 21494657381. The next prime is 21494657441. The reversal of 21494657408 is 80475649412.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70148 + ... + 218883.

It is an arithmetic number, because the mean of its divisors is an integer number (773883180).

Almost surely, 2^21494657408 is an apocalyptic number.

21494657408 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21494657408 is an abundant number, since it is smaller than the sum of its proper divisors (28033866112).

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

21494657408 is an equidigital number, since it uses as much as digits as its factorization.

21494657408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289135 (or 289123 counting only the distinct ones).

The product of its (nonzero) digits is 1935360, while the sum is 50.

The spelling of 21494657408 in words is "twenty-one billion, four hundred ninety-four million, six hundred fifty-seven thousand, four hundred eight".