66887531 has 2 divisors, whose sum is σ = 66887532. Its totient is φ = 66887530.

The previous prime is 66887521. The next prime is 66887551. The reversal of 66887531 is 13578866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66887531 - 2¹⁸ = 66625387 is a prime.

It is a super-2 number, since 2×66887531² = 8947883606551922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66887501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33443765 + 33443766.

It is an arithmetic number, because the mean of its divisors is an integer number (33443766).

Almost surely, 2^66887531 is an apocalyptic number.

66887531 is a deficient number, since it is larger than the sum of its proper divisors (1).

66887531 is an equidigital number, since it uses as much as digits as its factorization.

66887531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 44.

The square root of 66887531 is about 8178.4797487064. The cubic root of 66887531 is about 405.9274199490.

The spelling of 66887531 in words is "sixty-six million, eight hundred eighty-seven thousand, five hundred thirty-one".