642633517 has 2 divisors, whose sum is σ = 642633518. Its totient is φ = 642633516.

The previous prime is 642633493. The next prime is 642633529. The reversal of 642633517 is 715336246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 497334601 + 145298916 = 22301^2 + 12054^2 .

It is a cyclic number.

It is not a de Polignac number, because 642633517 - 2⁷ = 642633389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642633617) 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, 321316758 + 321316759.

It is an arithmetic number, because the mean of its divisors is an integer number (321316759).

Almost surely, 2^642633517 is an apocalyptic number.

It is an amenable number.

642633517 is a deficient number, since it is larger than the sum of its proper divisors (1).

642633517 is an equidigital number, since it uses as much as digits as its factorization.

642633517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 37.

The square root of 642633517 is about 25350.2172968991. The cubic root of 642633517 is about 862.9542876561.

The spelling of 642633517 in words is "six hundred forty-two million, six hundred thirty-three thousand, five hundred seventeen".