66191625 has 48 divisors (see below), whose sum is σ = 126376848. Its totient is φ = 33216000.

The previous prime is 66191621. The next prime is 66191627. The reversal of 66191625 is 52619166.

66191625 is a `hidden beast` number, since 6 + 619 + 16 + 25 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 22353984 + 43837641 = 4728^2 + 6621^2 .

It is not a de Polignac number, because 66191625 - 2² = 66191621 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66191625.

It is not an unprimeable number, because it can be changed into a prime (66191621) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 17395 + ... + 20855.

It is an arithmetic number, because the mean of its divisors is an integer number (2632851).

Almost surely, 2^66191625 is an apocalyptic number.

It is an amenable number.

66191625 is a deficient number, since it is larger than the sum of its proper divisors (60185223).

66191625 is a wasteful number, since it uses less digits than its factorization.

66191625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3499 (or 3486 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 66191625 is about 8135.8235600337. The cubic root of 66191625 is about 404.5147365856.

The spelling of 66191625 in words is "sixty-six million, one hundred ninety-one thousand, six hundred twenty-five".