21012120031 has 8 divisors (see below), whose sum is σ = 24018906240. Its totient is φ = 18006597528.

The previous prime is 21012119983. The next prime is 21012120047. The reversal of 21012120031 is 13002121012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21012120031 - 2⁷ = 21012119903 is a prime.

It is a super-2 number, since 2×21012120031² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21012119993 and 21012120020.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012120061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 280021 + ... + 347038.

It is an arithmetic number, because the mean of its divisors is an integer number (3002363280).

Almost surely, 2^21012120031 is an apocalyptic number.

21012120031 is a deficient number, since it is larger than the sum of its proper divisors (3006786209).

21012120031 is an equidigital number, since it uses as much as digits as its factorization.

21012120031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631853.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21012120031 its reverse (13002121012), we get a palindrome (34014241043).

The spelling of 21012120031 in words is "twenty-one billion, twelve million, one hundred twenty thousand, thirty-one".