2139125921 has 2 divisors, whose sum is σ = 2139125922. Its totient is φ = 2139125920.

The previous prime is 2139125893. The next prime is 2139125969. The reversal of 2139125921 is 1295219312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2119589521 + 19536400 = 46039^2 + 4420^2 .

It is a cyclic number.

It is not a de Polignac number, because 2139125921 - 2¹⁴ = 2139109537 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2139185921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1069562960 + 1069562961.

It is an arithmetic number, because the mean of its divisors is an integer number (1069562961).

Almost surely, 2^2139125921 is an apocalyptic number.

It is an amenable number.

2139125921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2139125921 is an equidigital number, since it uses as much as digits as its factorization.

2139125921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 35.

The square root of 2139125921 is about 46250.6856273504. The cubic root of 2139125921 is about 1288.4832685644.

The spelling of 2139125921 in words is "two billion, one hundred thirty-nine million, one hundred twenty-five thousand, nine hundred twenty-one".