66737561 has 16 divisors (see below), whose sum is σ = 74850048. Its totient is φ = 58990800.

The previous prime is 66737543. The next prime is 66737581. The reversal of 66737561 is 16573766.

It is not a de Polignac number, because 66737561 - 2¹⁴ = 66721177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66737521) 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, 60626 + ... + 61716.

It is an arithmetic number, because the mean of its divisors is an integer number (4678128).

Almost surely, 2^66737561 is an apocalyptic number.

It is an amenable number.

66737561 is a deficient number, since it is larger than the sum of its proper divisors (8112487).

66737561 is a wasteful number, since it uses less digits than its factorization.

66737561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1252.

The product of its digits is 158760, while the sum is 41.

The square root of 66737561 is about 8169.3060292781. The cubic root of 66737561 is about 405.6238133382.

The spelling of 66737561 in words is "sixty-six million, seven hundred thirty-seven thousand, five hundred sixty-one".