63666531 has 12 divisors (see below), whose sum is σ = 94102008. Its totient is φ = 41457024.

The previous prime is 63666523. The next prime is 63666539. The reversal of 63666531 is 13566636.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (63666523) and next prime (63666539).

It is not a de Polignac number, because 63666531 - 2³ = 63666523 is a prime.

It is a super-2 number, since 2×63666531² = 8106854339147922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (63666539) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 81870 + ... + 82643.

It is an arithmetic number, because the mean of its divisors is an integer number (7841834).

Almost surely, 2^63666531 is an apocalyptic number.

63666531 is a deficient number, since it is larger than the sum of its proper divisors (30435477).

63666531 is a wasteful number, since it uses less digits than its factorization.

63666531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164562 (or 164559 counting only the distinct ones).

The product of its digits is 58320, while the sum is 36.

The square root of 63666531 is about 7979.1309677182. The cubic root of 63666531 is about 399.3040627974.

The spelling of 63666531 in words is "sixty-three million, six hundred sixty-six thousand, five hundred thirty-one".