646021279 has 2 divisors, whose sum is σ = 646021280. Its totient is φ = 646021278.

The previous prime is 646021241. The next prime is 646021283. The reversal of 646021279 is 972120646.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 646021279 - 2²⁵ = 612466847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646021219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323010639 + 323010640.

It is an arithmetic number, because the mean of its divisors is an integer number (323010640).

Almost surely, 2^646021279 is an apocalyptic number.

646021279 is a deficient number, since it is larger than the sum of its proper divisors (1).

646021279 is an equidigital number, since it uses as much as digits as its factorization.

646021279 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 37.

The square root of 646021279 is about 25416.9486563592. The cubic root of 646021279 is about 864.4680387184.

The spelling of 646021279 in words is "six hundred forty-six million, twenty-one thousand, two hundred seventy-nine".