642739907 has 4 divisors (see below), whose sum is σ = 643191120. Its totient is φ = 642288696.

The previous prime is 642739871. The next prime is 642739921. The reversal of 642739907 is 709937246.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 642739907 - 2²⁰ = 641691331 is a prime.

It is a super-2 number, since 2×642739907² = 826229176100737298, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642739007) 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 in 3 ways as a sum of consecutive naturals, for example, 223463 + ... + 226320.

It is an arithmetic number, because the mean of its divisors is an integer number (160797780).

Almost surely, 2^642739907 is an apocalyptic number.

642739907 is a deficient number, since it is larger than the sum of its proper divisors (451213).

642739907 is a wasteful number, since it uses less digits than its factorization.

642739907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451212.

The product of its (nonzero) digits is 571536, while the sum is 47.

The square root of 642739907 is about 25352.3156141604. The cubic root of 642739907 is about 863.0019066272.

The spelling of 642739907 in words is "six hundred forty-two million, seven hundred thirty-nine thousand, nine hundred seven".