66512431 has 2 divisors, whose sum is σ = 66512432. Its totient is φ = 66512430.

The previous prime is 66512393. The next prime is 66512447. The reversal of 66512431 is 13421566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66512431 - 2¹³ = 66504239 is a prime.

It is a super-2 number, since 2×66512431² = 8847806955059522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 66512431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66512231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33256215 + 33256216.

It is an arithmetic number, because the mean of its divisors is an integer number (33256216).

Almost surely, 2^66512431 is an apocalyptic number.

66512431 is a deficient number, since it is larger than the sum of its proper divisors (1).

66512431 is an equidigital number, since it uses as much as digits as its factorization.

66512431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 28.

The square root of 66512431 is about 8155.5153730466. The cubic root of 66512431 is about 405.1671940891.

Adding to 66512431 its reverse (13421566), we get a palindrome (79933997).

The spelling of 66512431 in words is "sixty-six million, five hundred twelve thousand, four hundred thirty-one".