21535763580 has 72 divisors (see below), whose sum is σ = 66220054992. Its totient is φ = 5664197376.

The previous prime is 21535763567. The next prime is 21535763593. The reversal of 21535763580 is 8536753512.

21535763580 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 5 + 7 + 63 + 580 = 666.

It is an interprime number because it is at equal distance from previous prime (21535763567) and next prime (21535763593).

It is a super-2 number, since 2×21535763580² (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 23 ways as a sum of consecutive naturals, for example, 806334 + ... + 832613.

It is an arithmetic number, because the mean of its divisors is an integer number (919722986).

Almost surely, 2^21535763580 is an apocalyptic number.

21535763580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21535763580 is an abundant number, since it is smaller than the sum of its proper divisors (44684291412).

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

21535763580 is a wasteful number, since it uses less digits than its factorization.

21535763580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1639035 (or 1639030 counting only the distinct ones).

The product of its (nonzero) digits is 756000, while the sum is 45.

The spelling of 21535763580 in words is "twenty-one billion, five hundred thirty-five million, seven hundred sixty-three thousand, five hundred eighty".