642431749 has 2 divisors, whose sum is σ = 642431750. Its totient is φ = 642431748.

The previous prime is 642431731. The next prime is 642431759. The reversal of 642431749 is 947134246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 579942724 + 62489025 = 24082^2 + 7905^2 .

It is a cyclic number.

It is not a de Polignac number, because 642431749 - 2²³ = 634043141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642431719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321215874 + 321215875.

It is an arithmetic number, because the mean of its divisors is an integer number (321215875).

Almost surely, 2^642431749 is an apocalyptic number.

It is an amenable number.

642431749 is a deficient number, since it is larger than the sum of its proper divisors (1).

642431749 is an equidigital number, since it uses as much as digits as its factorization.

642431749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 40.

The square root of 642431749 is about 25346.2373736221. The cubic root of 642431749 is about 862.8639641245.

The spelling of 642431749 in words is "six hundred forty-two million, four hundred thirty-one thousand, seven hundred forty-nine".