66553631 has 2 divisors, whose sum is σ = 66553632. Its totient is φ = 66553630.

The previous prime is 66553607. The next prime is 66553649. The reversal of 66553631 is 13635566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66553631 - 2⁶ = 66553567 is a prime.

It is a super-2 number, since 2×66553631² = 8858771598568322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66553591 and 66553600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66555631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33276815 + 33276816.

It is an arithmetic number, because the mean of its divisors is an integer number (33276816).

Almost surely, 2^66553631 is an apocalyptic number.

66553631 is a deficient number, since it is larger than the sum of its proper divisors (1).

66553631 is an equidigital number, since it uses as much as digits as its factorization.

66553631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48600, while the sum is 35.

The square root of 66553631 is about 8158.0408800153. The cubic root of 66553631 is about 405.2508348092.

The spelling of 66553631 in words is "sixty-six million, five hundred fifty-three thousand, six hundred thirty-one".