1625979409 has 2 divisors, whose sum is σ = 1625979410. Its totient is φ = 1625979408.

The previous prime is 1625979401. The next prime is 1625979413. The reversal of 1625979409 is 9049795261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1600000000 + 25979409 = 40000^2 + 5097^2 .

It is a cyclic number.

It is not a de Polignac number, because 1625979409 - 2³ = 1625979401 is a prime.

It is not a weakly prime, because it can be changed into another prime (1625979401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 812989704 + 812989705.

It is an arithmetic number, because the mean of its divisors is an integer number (812989705).

Almost surely, 2^1625979409 is an apocalyptic number.

It is an amenable number.

1625979409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1625979409 is an equidigital number, since it uses as much as digits as its factorization.

1625979409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1224720, while the sum is 52.

The square root of 1625979409 is about 40323.4349851299. The cubic root of 1625979409 is about 1175.9034931777.

It can be divided in two parts, 16 and 25979409, that multiplied together give a square (415670544 = 20388²).

The spelling of 1625979409 in words is "one billion, six hundred twenty-five million, nine hundred seventy-nine thousand, four hundred nine".