21221535542031 has 80 divisors (see below), whose sum is σ = 35019034158240. Its totient is φ = 12700312289280.

The previous prime is 21221535541961. The next prime is 21221535542063. The reversal of 21221535542031 is 13024553512212.

21221535542031 is a `hidden beast` number, since 2 + 1 + 2 + 2 + 1 + 53 + 554 + 20 + 31 = 666.

It is not a de Polignac number, because 21221535542031 - 2⁹ = 21221535541519 is a prime.

It is a super-2 number, since 2×21221535542031² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221535542071) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 26691951 + ... + 27475503.

It is an arithmetic number, because the mean of its divisors is an integer number (437737926978).

Almost surely, 2^{21221535542031} is an apocalyptic number.

21221535542031 is a deficient number, since it is larger than the sum of its proper divisors (13797498616209).

21221535542031 is a wasteful number, since it uses less digits than its factorization.

21221535542031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783958 (or 783949 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The spelling of 21221535542031 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred thirty-five million, five hundred forty-two thousand, thirty-one".