66764421 has 24 divisors (see below), whose sum is σ = 100615424. Its totient is φ = 42612480.

The previous prime is 66764387. The next prime is 66764449. The reversal of 66764421 is 12446766.

66764421 is a `hidden beast` number, since 6 + 6 + 7 + 644 + 2 + 1 = 666.

It is not a de Polignac number, because 66764421 - 2⁹ = 66763909 is a prime.

It is a super-2 number, since 2×66764421² = 8914975822930482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66764221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25830 + ... + 28296.

Almost surely, 2^66764421 is an apocalyptic number.

It is an amenable number.

66764421 is a deficient number, since it is larger than the sum of its proper divisors (33851003).

66764421 is a wasteful number, since it uses less digits than its factorization.

66764421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2601 (or 2598 counting only the distinct ones).

The product of its digits is 48384, while the sum is 36.

The square root of 66764421 is about 8170.9498223891. The cubic root of 66764421 is about 405.6782234492.

The spelling of 66764421 in words is "sixty-six million, seven hundred sixty-four thousand, four hundred twenty-one".