66220431 has 4 divisors (see below), whose sum is σ = 88293912. Its totient is φ = 44146952.

The previous prime is 66220403. The next prime is 66220459. The reversal of 66220431 is 13402266.

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

It is an interprime number because it is at equal distance from previous prime (66220403) and next prime (66220459).

It is a cyclic number.

It is not a de Polignac number, because 66220431 - 2¹⁰ = 66219407 is a prime.

It is a super-2 number, since 2×66220431² = 8770290963651522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66220031) 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, 11036736 + ... + 11036741.

It is an arithmetic number, because the mean of its divisors is an integer number (22073478).

Almost surely, 2^66220431 is an apocalyptic number.

66220431 is a deficient number, since it is larger than the sum of its proper divisors (22073481).

66220431 is a wasteful number, since it uses less digits than its factorization.

66220431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22073480.

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 66220431 is about 8137.5936860966. The cubic root of 66220431 is about 404.5734084673.

Adding to 66220431 its reverse (13402266), we get a palindrome (79622697).

The spelling of 66220431 in words is "sixty-six million, two hundred twenty thousand, four hundred thirty-one".