21534510684 has 12 divisors (see below), whose sum is σ = 50247191624. Its totient is φ = 7178170224.

The previous prime is 21534510671. The next prime is 21534510707. The reversal of 21534510684 is 48601543512.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 897271267 + ... + 897271290.

Almost surely, 2^21534510684 is an apocalyptic number.

It is an amenable number.

21534510684 is an abundant number, since it is smaller than the sum of its proper divisors (28712680940).

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

21534510684 is a wasteful number, since it uses less digits than its factorization.

21534510684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1794542564 (or 1794542562 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 39.

The spelling of 21534510684 in words is "twenty-one billion, five hundred thirty-four million, five hundred ten thousand, six hundred eighty-four".