642634439 has 2 divisors, whose sum is σ = 642634440. Its totient is φ = 642634438.

The previous prime is 642634423. The next prime is 642634457. The reversal of 642634439 is 934436246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642634439 - 2⁴ = 642634423 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 642634396 and 642634405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642634339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321317219 + 321317220.

It is an arithmetic number, because the mean of its divisors is an integer number (321317220).

Almost surely, 2^642634439 is an apocalyptic number.

642634439 is a deficient number, since it is larger than the sum of its proper divisors (1).

642634439 is an equidigital number, since it uses as much as digits as its factorization.

642634439 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 41.

The square root of 642634439 is about 25350.2354821410. The cubic root of 642634439 is about 862.9547003556.

The spelling of 642634439 in words is "six hundred forty-two million, six hundred thirty-four thousand, four hundred thirty-nine".