21521010215131 has 4 divisors (see below), whose sum is σ = 24595440245872. Its totient is φ = 18446580184392.

The previous prime is 21521010215123. The next prime is 21521010215143. The reversal of 21521010215131 is 13151201012512.

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 21521010215131 - 2³ = 21521010215123 is a prime.

It is a super-2 number, since 2×21521010215131² (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 = 21521010215096 and 21521010215105.

It is not an unprimeable number, because it can be changed into a prime (21521010225131) 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, 1537215015360 + ... + 1537215015373.

It is an arithmetic number, because the mean of its divisors is an integer number (6148860061468).

Almost surely, 2^{21521010215131} is an apocalyptic number.

21521010215131 is a deficient number, since it is larger than the sum of its proper divisors (3074430030741).

21521010215131 is an equidigital number, since it uses as much as digits as its factorization.

21521010215131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3074430030740.

The product of its (nonzero) digits is 600, while the sum is 25.

Adding to 21521010215131 its reverse (13151201012512), we get a palindrome (34672211227643).

The spelling of 21521010215131 in words is "twenty-one trillion, five hundred twenty-one billion, ten million, two hundred fifteen thousand, one hundred thirty-one".