642706691 has 8 divisors (see below), whose sum is σ = 703392768. Its totient is φ = 582397000.

The previous prime is 642706667. The next prime is 642706699. The reversal of 642706691 is 196607246.

642706691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 642706691 - 2²² = 638512387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642706699) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90515 + ... + 97356.

It is an arithmetic number, because the mean of its divisors is an integer number (87924096).

Almost surely, 2^642706691 is an apocalyptic number.

642706691 is a deficient number, since it is larger than the sum of its proper divisors (60686077).

642706691 is a wasteful number, since it uses less digits than its factorization.

642706691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188193.

The product of its (nonzero) digits is 108864, while the sum is 41.

The square root of 642706691 is about 25351.6605176071. The cubic root of 642706691 is about 862.9870400823.

The spelling of 642706691 in words is "six hundred forty-two million, seven hundred six thousand, six hundred ninety-one".