661153439 has 2 divisors, whose sum is σ = 661153440. Its totient is φ = 661153438.

The previous prime is 661153403. The next prime is 661153453. The reversal of 661153439 is 934351166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661153439 - 2¹² = 661149343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661153039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330576719 + 330576720.

It is an arithmetic number, because the mean of its divisors is an integer number (330576720).

Almost surely, 2^661153439 is an apocalyptic number.

661153439 is a deficient number, since it is larger than the sum of its proper divisors (1).

661153439 is an equidigital number, since it uses as much as digits as its factorization.

661153439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 38.

The square root of 661153439 is about 25712.9041339169. The cubic root of 661153439 is about 871.1656718070.

The spelling of 661153439 in words is "six hundred sixty-one million, one hundred fifty-three thousand, four hundred thirty-nine".