661623337 has 2 divisors, whose sum is σ = 661623338. Its totient is φ = 661623336.

The previous prime is 661623329. The next prime is 661623343. The reversal of 661623337 is 733326166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 620458281 + 41165056 = 24909^2 + 6416^2 .

It is a cyclic number.

It is not a de Polignac number, because 661623337 - 2³ = 661623329 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661623296 and 661623305.

It is not a weakly prime, because it can be changed into another prime (661623637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330811668 + 330811669.

It is an arithmetic number, because the mean of its divisors is an integer number (330811669).

Almost surely, 2^661623337 is an apocalyptic number.

It is an amenable number.

661623337 is a deficient number, since it is larger than the sum of its proper divisors (1).

661623337 is an equidigital number, since it uses as much as digits as its factorization.

661623337 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 37.

The square root of 661623337 is about 25722.0399074412. The cubic root of 661623337 is about 871.3720092170.

The spelling of 661623337 in words is "six hundred sixty-one million, six hundred twenty-three thousand, three hundred thirty-seven".