8125039921 has 2 divisors, whose sum is σ = 8125039922. Its totient is φ = 8125039920.

The previous prime is 8125039907. The next prime is 8125039943. The reversal of 8125039921 is 1299305218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7414071025 + 710968896 = 86105^2 + 26664^2 .

It is a cyclic number.

It is not a de Polignac number, because 8125039921 - 2¹¹ = 8125037873 is a prime.

It is not a weakly prime, because it can be changed into another prime (8125039981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4062519960 + 4062519961.

It is an arithmetic number, because the mean of its divisors is an integer number (4062519961).

Almost surely, 2^8125039921 is an apocalyptic number.

It is an amenable number.

8125039921 is a deficient number, since it is larger than the sum of its proper divisors (1).

8125039921 is an equidigital number, since it uses as much as digits as its factorization.

8125039921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 8125039921 is about 90139.0033281931. The cubic root of 8125039921 is about 2010.3661718305.

The spelling of 8125039921 in words is "eight billion, one hundred twenty-five million, thirty-nine thousand, nine hundred twenty-one".