21507724466513 has 4 divisors (see below), whose sum is σ = 21567634562880. Its totient is φ = 21447814370148.

The previous prime is 21507724466479. The next prime is 21507724466519. The reversal of 21507724466513 is 31566442770512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21507724466513 - 2¹² = 21507724462417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21507724466519) 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, 29955047645 + ... + 29955048362.

It is an arithmetic number, because the mean of its divisors is an integer number (5391908640720).

Almost surely, 2^{21507724466513} is an apocalyptic number.

It is an amenable number.

21507724466513 is a deficient number, since it is larger than the sum of its proper divisors (59910096367).

21507724466513 is an equidigital number, since it uses as much as digits as its factorization.

21507724466513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59910096366.

The product of its (nonzero) digits is 8467200, while the sum is 53.

The spelling of 21507724466513 in words is "twenty-one trillion, five hundred seven billion, seven hundred twenty-four million, four hundred sixty-six thousand, five hundred thirteen".