66653657 has 16 divisors (see below), whose sum is σ = 77952000. Its totient is φ = 55812240.

The previous prime is 66653641. The next prime is 66653681. The reversal of 66653657 is 75635666.

It is a cyclic number.

It is not a de Polignac number, because 66653657 - 2⁴ = 66653641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66653357) 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, 81782 + ... + 82592.

It is an arithmetic number, because the mean of its divisors is an integer number (4872000).

Almost surely, 2^66653657 is an apocalyptic number.

It is an amenable number.

66653657 is a deficient number, since it is larger than the sum of its proper divisors (11298343).

66653657 is a wasteful number, since it uses less digits than its factorization.

66653657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1076.

The product of its digits is 680400, while the sum is 44.

The square root of 66653657 is about 8164.1690942802. The cubic root of 66653657 is about 405.4537555155.

Subtracting 66653657 from its reverse (75635666), we obtain a square (8982009 = 2997²).

The spelling of 66653657 in words is "sixty-six million, six hundred fifty-three thousand, six hundred fifty-seven".