66257649 has 16 divisors (see below), whose sum is σ = 99825600. Its totient is φ = 43422048.

The previous prime is 66257593. The next prime is 66257657. The reversal of 66257649 is 94675266.

It is not a de Polignac number, because 66257649 - 2²¹ = 64160497 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (66257749) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19204 + ... + 22389.

It is an arithmetic number, because the mean of its divisors is an integer number (6239100).

Almost surely, 2^66257649 is an apocalyptic number.

It is an amenable number.

66257649 is a deficient number, since it is larger than the sum of its proper divisors (33567951).

66257649 is a wasteful number, since it uses less digits than its factorization.

66257649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41661 (or 41655 counting only the distinct ones).

The product of its digits is 544320, while the sum is 45.

The square root of 66257649 is about 8139.8801588230. The cubic root of 66257649 is about 404.6491886701.

It can be divided in two parts, 662 and 57649, that added together give a triangular number (58311 = T₃₄₁).

The spelling of 66257649 in words is "sixty-six million, two hundred fifty-seven thousand, six hundred forty-nine".