66679531 has 4 divisors (see below), whose sum is σ = 70189000. Its totient is φ = 63170064.

The previous prime is 66679519. The next prime is 66679537. The reversal of 66679531 is 13597666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66679531 - 2¹⁵ = 66646763 is a prime.

It is a super-2 number, since 2×66679531² = 8892319708759922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66679537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1754706 + ... + 1754743.

It is an arithmetic number, because the mean of its divisors is an integer number (17547250).

Almost surely, 2^66679531 is an apocalyptic number.

66679531 is the 4715-th hex number.

66679531 is a deficient number, since it is larger than the sum of its proper divisors (3509469).

66679531 is a wasteful number, since it uses less digits than its factorization.

66679531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3509468.

The product of its digits is 204120, while the sum is 43.

The square root of 66679531 is about 8165.7535475913. The cubic root of 66679531 is about 405.5062125188.

The spelling of 66679531 in words is "sixty-six million, six hundred seventy-nine thousand, five hundred thirty-one".