66401575 has 24 divisors (see below), whose sum is σ = 90985248. Its totient is φ = 47815680.

The previous prime is 66401563. The next prime is 66401593. The reversal of 66401575 is 57510466.

It is a happy number.

It is not a de Polignac number, because 66401575 - 2⁹ = 66401063 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66401575.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6379 + ... + 13171.

It is an arithmetic number, because the mean of its divisors is an integer number (3791052).

Almost surely, 2^66401575 is an apocalyptic number.

66401575 is a deficient number, since it is larger than the sum of its proper divisors (24583673).

66401575 is a wasteful number, since it uses less digits than its factorization.

66401575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6843 (or 6838 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 66401575 is about 8148.7161565488. The cubic root of 66401575 is about 404.9419720754.

The spelling of 66401575 in words is "sixty-six million, four hundred one thousand, five hundred seventy-five".