66917961 has 24 divisors (see below), whose sum is σ = 108974880. Its totient is φ = 40554360.

The previous prime is 66917947. The next prime is 66917987. The reversal of 66917961 is 16971966.

It is not a de Polignac number, because 66917961 - 2¹⁵ = 66885193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66917161) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6975 + ... + 13508.

It is an arithmetic number, because the mean of its divisors is an integer number (4540620).

Almost surely, 2^66917961 is an apocalyptic number.

It is an amenable number.

66917961 is a deficient number, since it is larger than the sum of its proper divisors (42056919).

66917961 is a wasteful number, since it uses less digits than its factorization.

66917961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20514 (or 20497 counting only the distinct ones).

The product of its digits is 122472, while the sum is 45.

The square root of 66917961 is about 8180.3399073633. The cubic root of 66917961 is about 405.9889685339.

The spelling of 66917961 in words is "sixty-six million, nine hundred seventeen thousand, nine hundred sixty-one".