66861957 has 16 divisors (see below), whose sum is σ = 90179712. Its totient is φ = 44063040.

The previous prime is 66861953. The next prime is 66861959. The reversal of 66861957 is 75916866.

It is not a de Polignac number, because 66861957 - 2² = 66861953 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66861953) 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, 158607 + ... + 159027.

It is an arithmetic number, because the mean of its divisors is an integer number (5636232).

Almost surely, 2^66861957 is an apocalyptic number.

It is an amenable number.

66861957 is a deficient number, since it is larger than the sum of its proper divisors (23317755).

66861957 is a wasteful number, since it uses less digits than its factorization.

66861957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908.

The product of its digits is 544320, while the sum is 48.

The square root of 66861957 is about 8176.9161057210. The cubic root of 66861957 is about 405.8756788097.

The spelling of 66861957 in words is "sixty-six million, eight hundred sixty-one thousand, nine hundred fifty-seven".