625166665 has 4 divisors (see below), whose sum is σ = 750200004. Its totient is φ = 500133328.

The previous prime is 625166639. The next prime is 625166681. The reversal of 625166665 is 566661526.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 566661526 = 2 ⋅283330763.

It can be written as a sum of positive squares in 2 ways, for example, as 275925321 + 349241344 = 16611^2 + 18688^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-625166665 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62516662 + ... + 62516671.

It is an arithmetic number, because the mean of its divisors is an integer number (187550001).

Almost surely, 2^625166665 is an apocalyptic number.

It is an amenable number.

625166665 is a deficient number, since it is larger than the sum of its proper divisors (125033339).

625166665 is a wasteful number, since it uses less digits than its factorization.

625166665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125033338.

The product of its digits is 388800, while the sum is 43.

The square root of 625166665 is about 25003.3330778118. Note that the first 3 decimals coincide. The cubic root of 625166665 is about 855.0639647550.

The spelling of 625166665 in words is "six hundred twenty-five million, one hundred sixty-six thousand, six hundred sixty-five".