66978463 has 8 divisors (see below), whose sum is σ = 68005440. Its totient is φ = 65957760.

The previous prime is 66978451. The next prime is 66978481. The reversal of 66978463 is 36487966.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66978463 - 2⁹ = 66977951 is a prime.

It is a super-2 number, since 2×66978463² = 8972229011684738, 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 (66978433) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22731 + ... + 25507.

It is an arithmetic number, because the mean of its divisors is an integer number (8500680).

Almost surely, 2^66978463 is an apocalyptic number.

66978463 is a deficient number, since it is larger than the sum of its proper divisors (1026977).

66978463 is a wasteful number, since it uses less digits than its factorization.

66978463 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3137.

The product of its digits is 1306368, while the sum is 49.

The square root of 66978463 is about 8184.0370844712. The cubic root of 66978463 is about 406.1112861959. Note that the first 3 decimals are identical.

The spelling of 66978463 in words is "sixty-six million, nine hundred seventy-eight thousand, four hundred sixty-three".