21020053031 has 4 divisors (see below), whose sum is σ = 21021247632. Its totient is φ = 21018858432.

The previous prime is 21020052973. The next prime is 21020053111. The reversal of 21020053031 is 13035002012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21020053031 - 2¹⁰ = 21020052007 is a prime.

It is a super-2 number, since 2×21020053031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020053231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 570506 + ... + 606231.

It is an arithmetic number, because the mean of its divisors is an integer number (5255311908).

Almost surely, 2^21020053031 is an apocalyptic number.

21020053031 is a deficient number, since it is larger than the sum of its proper divisors (1194601).

21020053031 is a wasteful number, since it uses less digits than its factorization.

21020053031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1194600.

The product of its (nonzero) digits is 180, while the sum is 17.

Adding to 21020053031 its reverse (13035002012), we get a palindrome (34055055043).

The spelling of 21020053031 in words is "twenty-one billion, twenty million, fifty-three thousand, thirty-one".