66415531 has 24 divisors (see below), whose sum is σ = 85264704. Its totient is φ = 51246720.

The previous prime is 66415529. The next prime is 66415541. The reversal of 66415531 is 13551466.

It is not a de Polignac number, because 66415531 - 2¹ = 66415529 is a prime.

It is a super-2 number, since 2×66415531² = 8822045516023922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66415493 and 66415502.

It is not an unprimeable number, because it can be changed into a prime (66415501) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24846 + ... + 27388.

It is an arithmetic number, because the mean of its divisors is an integer number (3552696).

Almost surely, 2^66415531 is an apocalyptic number.

66415531 is a deficient number, since it is larger than the sum of its proper divisors (18849173).

66415531 is a wasteful number, since it uses less digits than its factorization.

66415531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2611 (or 2604 counting only the distinct ones).

The product of its digits is 10800, while the sum is 31.

The square root of 66415531 is about 8149.5724427727. The cubic root of 66415531 is about 404.9703397473.

Adding to 66415531 its reverse (13551466), we get a palindrome (79966997).

The spelling of 66415531 in words is "sixty-six million, four hundred fifteen thousand, five hundred thirty-one".