66557461625 has 16 divisors (see below), whose sum is σ = 83132379408. Its totient is φ = 53201952000.

The previous prime is 66557461603. The next prime is 66557461631. The reversal of 66557461625 is 52616475566.

It can be written as a sum of positive squares in 8 ways, for example, as 43522721641 + 23034739984 = 208621^2 + 151772^2 .

It is not a de Polignac number, because 66557461625 - 2¹⁶ = 66557396089 is a prime.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67856 + ... + 371105.

It is an arithmetic number, because the mean of its divisors is an integer number (5195773713).

Almost surely, 2^66557461625 is an apocalyptic number.

It is an amenable number.

66557461625 is a deficient number, since it is larger than the sum of its proper divisors (16574917783).

66557461625 is a wasteful number, since it uses less digits than its factorization.

66557461625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440189 (or 440179 counting only the distinct ones).

The product of its digits is 9072000, while the sum is 53.

The spelling of 66557461625 in words is "sixty-six billion, five hundred fifty-seven million, four hundred sixty-one thousand, six hundred twenty-five".