21500121303031 has 16 divisors (see below), whose sum is σ = 24877728937984. Its totient is φ = 18200029143744.

The previous prime is 21500121303019. The next prime is 21500121303077. The reversal of 21500121303031 is 13030312100512.

It is not a de Polignac number, because 21500121303031 - 2⁷ = 21500121302903 is a prime.

It is a super-2 number, since 2×21500121303031² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21500121302993 and 21500121303011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500121306031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40361910 + ... + 40891123.

It is an arithmetic number, because the mean of its divisors is an integer number (1554858058624).

Almost surely, 2^{21500121303031} is an apocalyptic number.

21500121303031 is a deficient number, since it is larger than the sum of its proper divisors (3377607634953).

21500121303031 is a wasteful number, since it uses less digits than its factorization.

21500121303031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81253510.

The product of its (nonzero) digits is 540, while the sum is 22.

Adding to 21500121303031 its reverse (13030312100512), we get a palindrome (34530433403543).

The spelling of 21500121303031 in words is "twenty-one trillion, five hundred billion, one hundred twenty-one million, three hundred three thousand, thirty-one".