21154506360121 has 16 divisors (see below), whose sum is σ = 21426692149008. Its totient is φ = 20883563008000.

The previous prime is 21154506360107. The next prime is 21154506360131. The reversal of 21154506360121 is 12106360545112.

It can be written as a sum of positive squares in 8 ways, for example, as 3799458608400 + 17355047751721 = 1949220^2 + 4165939^2 .

It is a cyclic number.

It is not a de Polignac number, because 21154506360121 - 2⁵ = 21154506360089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21154506360131) 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, 429273135 + ... + 429322411.

It is an arithmetic number, because the mean of its divisors is an integer number (1339168259313).

Almost surely, 2^{21154506360121} is an apocalyptic number.

It is an amenable number.

21154506360121 is a deficient number, since it is larger than the sum of its proper divisors (272185788887).

21154506360121 is a wasteful number, since it uses less digits than its factorization.

21154506360121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61772.

The product of its (nonzero) digits is 43200, while the sum is 37.

The spelling of 21154506360121 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred six million, three hundred sixty thousand, one hundred twenty-one".