661626311 has 2 divisors, whose sum is σ = 661626312. Its totient is φ = 661626310.

The previous prime is 661626299. The next prime is 661626319. The reversal of 661626311 is 113626166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661626311 - 2²⁶ = 594517447 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661626319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330813155 + 330813156.

It is an arithmetic number, because the mean of its divisors is an integer number (330813156).

Almost surely, 2^661626311 is an apocalyptic number.

661626311 is a deficient number, since it is larger than the sum of its proper divisors (1).

661626311 is an equidigital number, since it uses as much as digits as its factorization.

661626311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The square root of 661626311 is about 25722.0977177212. The cubic root of 661626311 is about 871.3733148221.

The spelling of 661626311 in words is "six hundred sixty-one million, six hundred twenty-six thousand, three hundred eleven".