647542639 has 2 divisors, whose sum is σ = 647542640. Its totient is φ = 647542638.

The previous prime is 647542603. The next prime is 647542657. The reversal of 647542639 is 936245746.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 647542639 - 2¹⁵ = 647509871 is a prime.

It is a super-2 number, since 2×647542639² = 838622938646168642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647542939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323771319 + 323771320.

It is an arithmetic number, because the mean of its divisors is an integer number (323771320).

Almost surely, 2^647542639 is an apocalyptic number.

647542639 is a deficient number, since it is larger than the sum of its proper divisors (1).

647542639 is an equidigital number, since it uses as much as digits as its factorization.

647542639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 46.

The square root of 647542639 is about 25446.8591185631. The cubic root of 647542639 is about 865.1461051609.

The spelling of 647542639 in words is "six hundred forty-seven million, five hundred forty-two thousand, six hundred thirty-nine".