66211431 has 16 divisors (see below), whose sum is σ = 103716480. Its totient is φ = 37041120.

The previous prime is 66211427. The next prime is 66211451. The reversal of 66211431 is 13411266.

It is not a de Polignac number, because 66211431 - 2² = 66211427 is a prime.

It is a super-2 number, since 2×66211431² = 8767907190135522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66211421) 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, 76741 + ... + 77598.

It is an arithmetic number, because the mean of its divisors is an integer number (6482280).

Almost surely, 2^66211431 is an apocalyptic number.

66211431 is a deficient number, since it is larger than the sum of its proper divisors (37505049).

66211431 is a wasteful number, since it uses less digits than its factorization.

66211431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154366.

The product of its digits is 864, while the sum is 24.

The square root of 66211431 is about 8137.0406782810. The cubic root of 66211431 is about 404.5550791511. Note that the first 3 decimals are identical.

Adding to 66211431 its reverse (13411266), we get a palindrome (79622697).

The spelling of 66211431 in words is "sixty-six million, two hundred eleven thousand, four hundred thirty-one".