1625440561 has 4 divisors (see below), whose sum is σ = 1625656932. Its totient is φ = 1625224192.

The previous prime is 1625440547. The next prime is 1625440573. The reversal of 1625440561 is 1650445261.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1072955536 + 552485025 = 32756^2 + 23505^2 .

It is a cyclic number.

It is not a de Polignac number, because 1625440561 - 2⁵ = 1625440529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1625440511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96496 + ... + 112081.

It is an arithmetic number, because the mean of its divisors is an integer number (406414233).

Almost surely, 2^1625440561 is an apocalyptic number.

It is an amenable number.

1625440561 is a deficient number, since it is larger than the sum of its proper divisors (216371).

1625440561 is an equidigital number, since it uses as much as digits as its factorization.

1625440561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216370.

The product of its (nonzero) digits is 28800, while the sum is 34.

The square root of 1625440561 is about 40316.7528578381. The cubic root of 1625440561 is about 1175.7735810664.

The spelling of 1625440561 in words is "one billion, six hundred twenty-five million, four hundred forty thousand, five hundred sixty-one".