642664373 has 4 divisors (see below), whose sum is σ = 692100108. Its totient is φ = 593228640.

The previous prime is 642664361. The next prime is 642664409. The reversal of 642664373 is 373466246.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 373466246 = 2 ⋅186733123.

It can be written as a sum of positive squares in 2 ways, for example, as 30448324 + 612216049 = 5518^2 + 24743^2 .

It is a cyclic number.

It is not a de Polignac number, because 642664373 - 2⁸ = 642664117 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 642664373.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642660373) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24717848 + ... + 24717873.

It is an arithmetic number, because the mean of its divisors is an integer number (173025027).

Almost surely, 2^642664373 is an apocalyptic number.

It is an amenable number.

642664373 is a deficient number, since it is larger than the sum of its proper divisors (49435735).

642664373 is a wasteful number, since it uses less digits than its factorization.

642664373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49435734.

The product of its digits is 435456, while the sum is 41.

The square root of 642664373 is about 25350.8258839826. The cubic root of 642664373 is about 862.9680989968.

The spelling of 642664373 in words is "six hundred forty-two million, six hundred sixty-four thousand, three hundred seventy-three".