125001590128921 has 9 divisors (see below), whose sum is σ = 137398577223999. Its totient is φ = 113637697404000.

The previous prime is 125001590128889. The next prime is 125001590128937. The reversal of 125001590128921 is 129821095100521.

The square root of 125001590128921 is 11180411.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 118018043959321 + 6983546169600 = 10863611^2 + 2642640^2 .

It is not a de Polignac number, because 125001590128921 - 2⁵ = 125001590128889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (125001590128981) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 122476321 + ... + 123492721.

Almost surely, 2^{125001590128921} is an apocalyptic number.

125001590128921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

125001590128921 is the 11180411-st square number.

125001590128921 is the 5590206-th centered octagonal number.

It is an amenable number.

125001590128921 is a deficient number, since it is larger than the sum of its proper divisors (12396987095078).

125001590128921 is an frugal number, since it uses more digits than its factorization.

125001590128921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2032824 (or 1016412 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 46.

The spelling of 125001590128921 in words is "one hundred twenty-five trillion, one billion, five hundred ninety million, one hundred twenty-eight thousand, nine hundred twenty-one".