21020403912031 has 4 divisors (see below), whose sum is σ = 21021099038464. Its totient is φ = 21019708785600.

The previous prime is 21020403912029. The next prime is 21020403912041. The reversal of 21020403912031 is 13021930402012.

It is a happy number.

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 21020403912031 - 2¹ = 21020403912029 is a prime.

It is a super-2 number, since 2×21020403912031² (a number of 27 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 (21020403912041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 347517855 + ... + 347578336.

It is an arithmetic number, because the mean of its divisors is an integer number (5255274759616).

Almost surely, 2^{21020403912031} is an apocalyptic number.

21020403912031 is a deficient number, since it is larger than the sum of its proper divisors (695126433).

21020403912031 is an equidigital number, since it uses as much as digits as its factorization.

21020403912031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 695126432.

The product of its (nonzero) digits is 2592, while the sum is 28.

The spelling of 21020403912031 in words is "twenty-one trillion, twenty billion, four hundred three million, nine hundred twelve thousand, thirty-one".