21451002608640 has 176 divisors, whose sum is σ = 74846936396160. Its totient is φ = 5200243015680.

The previous prime is 21451002608599. The next prime is 21451002608663. The reversal of 21451002608640 is 4680620015412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (176).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63310570 + ... + 63648489.

Almost surely, 2^{21451002608640} is an apocalyptic number.

21451002608640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21451002608640 is an abundant number, since it is smaller than the sum of its proper divisors (53395933787520).

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

21451002608640 is a wasteful number, since it uses less digits than its factorization.

21451002608640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126959098 (or 126959080 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 39.

The spelling of 21451002608640 in words is "twenty-one trillion, four hundred fifty-one billion, two million, six hundred eight thousand, six hundred forty".