21530533131 has 14 divisors (see below), whose sum is σ = 32281033620. Its totient is φ = 14353688268.

The previous prime is 21530533121. The next prime is 21530533153. The reversal of 21530533131 is 13133503512.

21530533131 is a `hidden beast` number, since 21 + 5 + 305 + 331 + 3 + 1 = 666.

It is not a de Polignac number, because 21530533131 - 2¹¹ = 21530531083 is a prime.

It is a super-2 number, since 2×21530533131² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21530533095 and 21530533104.

It is not an unprimeable number, because it can be changed into a prime (21530533111) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 14766441 + ... + 14767898.

Almost surely, 2^21530533131 is an apocalyptic number.

21530533131 is a deficient number, since it is larger than the sum of its proper divisors (10750500489).

21530533131 is an frugal number, since it uses more digits than its factorization.

21530533131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29534357 (or 29534342 counting only the distinct ones).

The product of its (nonzero) digits is 4050, while the sum is 27.

The spelling of 21530533131 in words is "twenty-one billion, five hundred thirty million, five hundred thirty-three thousand, one hundred thirty-one".