21356632530 has 320 divisors, whose sum is σ = 61394927616. Its totient is φ = 5318784000.

The previous prime is 21356632519. The next prime is 21356632553. The reversal of 21356632530 is 3523665312.

21356632530 is a `hidden beast` number, since 2 + 1 + 35 + 66 + 32 + 530 = 666.

It is a super-2 number, since 2×21356632530² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 111814735 + ... + 111814925.

Almost surely, 2^21356632530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21356632530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30697463808).

21356632530 is an abundant number, since it is smaller than the sum of its proper divisors (40038295086).

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

21356632530 is a wasteful number, since it uses less digits than its factorization.

21356632530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 97200, while the sum is 36.

The spelling of 21356632530 in words is "twenty-one billion, three hundred fifty-six million, six hundred thirty-two thousand, five hundred thirty".