66978574 has 32 divisors (see below), whose sum is σ = 112724640. Its totient is φ = 29635200.

The previous prime is 66978559. The next prime is 66978577. The reversal of 66978574 is 47587966.

It is a happy number.

It is a super-2 number, since 2×66978574² = 8972258750146952, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66978577) 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, 158884 + ... + 159304.

It is an arithmetic number, because the mean of its divisors is an integer number (3522645).

Almost surely, 2^66978574 is an apocalyptic number.

66978574 is a deficient number, since it is larger than the sum of its proper divisors (45746066).

66978574 is a wasteful number, since it uses less digits than its factorization.

66978574 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676.

The product of its digits is 2540160, while the sum is 52.

The square root of 66978574 is about 8184.0438659626. The cubic root of 66978574 is about 406.1115105383. Note that the first 3 decimals are identical.

The spelling of 66978574 in words is "sixty-six million, nine hundred seventy-eight thousand, five hundred seventy-four".