625477909681 has 4 divisors (see below), whose sum is σ = 631926135652. Its totient is φ = 619029683712.

The previous prime is 625477909627. The next prime is 625477909711. The reversal of 625477909681 is 186909774526.

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 492551312400 + 132926597281 = 701820^2 + 364591^2 .

It is a cyclic number.

It is not a de Polignac number, because 625477909681 - 2¹¹ = 625477907633 is a prime.

It is a super-2 number, since 2×625477909681² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (625477909081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3224112840 + ... + 3224113033.

It is an arithmetic number, because the mean of its divisors is an integer number (157981533913).

Almost surely, 2^625477909681 is an apocalyptic number.

It is an amenable number.

625477909681 is a deficient number, since it is larger than the sum of its proper divisors (6448225971).

625477909681 is an equidigital number, since it uses as much as digits as its factorization.

625477909681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6448225970.

The product of its (nonzero) digits is 45722880, while the sum is 64.

The spelling of 625477909681 in words is "six hundred twenty-five billion, four hundred seventy-seven million, nine hundred nine thousand, six hundred eighty-one".