642681397 has 8 divisors (see below), whose sum is σ = 659963744. Its totient is φ = 625505328.

The previous prime is 642681359. The next prime is 642681409. The reversal of 642681397 is 793186246.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642681397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642681097) 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, 14238 + ... + 38575.

It is an arithmetic number, because the mean of its divisors is an integer number (82495468).

Almost surely, 2^642681397 is an apocalyptic number.

642681397 is the 14637-th hex number.

It is an amenable number.

642681397 is a deficient number, since it is larger than the sum of its proper divisors (17282347).

642681397 is a wasteful number, since it uses less digits than its factorization.

642681397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53139.

The product of its digits is 435456, while the sum is 46.

The square root of 642681397 is about 25351.1616499126. The cubic root of 642681397 is about 862.9757188576.

The spelling of 642681397 in words is "six hundred forty-two million, six hundred eighty-one thousand, three hundred ninety-seven".