21154520661213 has 16 divisors (see below), whose sum is σ = 29547999187200. Its totient is φ = 13444339621440.

The previous prime is 21154520661193. The next prime is 21154520661221. The reversal of 21154520661213 is 31216602545112.

It is not a de Polignac number, because 21154520661213 - 2¹⁸ = 21154520399069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154520661223) 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, 1538951418 + ... + 1538965163.

It is an arithmetic number, because the mean of its divisors is an integer number (1846749949200).

Almost surely, 2^{21154520661213} is an apocalyptic number.

It is an amenable number.

21154520661213 is a deficient number, since it is larger than the sum of its proper divisors (8393478525987).

21154520661213 is a wasteful number, since it uses less digits than its factorization.

21154520661213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3077916692.

The product of its (nonzero) digits is 86400, while the sum is 39.

The spelling of 21154520661213 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred twenty million, six hundred sixty-one thousand, two hundred thirteen".