21010542021 has 64 divisors (see below), whose sum is σ = 38400307200. Its totient is φ = 11087955648.

The previous prime is 21010541999. The next prime is 21010542031. The reversal of 21010542021 is 12024501012.

21010542021 is a `hidden beast` number, since 2 + 101 + 0 + 542 + 0 + 21 = 666.

It is not a de Polignac number, because 21010542021 - 2¹⁸ = 21010279877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21010541985 and 21010542003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010542031) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42730 + ... + 209396.

It is an arithmetic number, because the mean of its divisors is an integer number (600004800).

Almost surely, 2^21010542021 is an apocalyptic number.

21010542021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21010542021 is a deficient number, since it is larger than the sum of its proper divisors (17389765179).

21010542021 is a wasteful number, since it uses less digits than its factorization.

21010542021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166735 (or 166729 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The spelling of 21010542021 in words is "twenty-one billion, ten million, five hundred forty-two thousand, twenty-one".