21642639480 has 1056 divisors, whose sum is σ = 98145969840. Its totient is φ = 4232632320.

The previous prime is 21642639443. The next prime is 21642639563. The reversal of 21642639480 is 8493624612.

21642639480 is a `hidden beast` number, since 2 + 1 + 6 + 4 + 2 + 639 + 4 + 8 + 0 = 666.

It is a super-2 number, since 2×21642639480² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 263 ways as a sum of consecutive naturals, for example, 1273096432 + ... + 1273096448.

Almost surely, 2^21642639480 is an apocalyptic number.

21642639480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21642639480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49072984920).

21642639480 is an abundant number, since it is smaller than the sum of its proper divisors (76503330360).

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

21642639480 is a wasteful number, since it uses less digits than its factorization.

21642639480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 45 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The spelling of 21642639480 in words is "twenty-one billion, six hundred forty-two million, six hundred thirty-nine thousand, four hundred eighty".