642702649 has 4 divisors (see below), whose sum is σ = 653238820. Its totient is φ = 632166480.

The previous prime is 642702647. The next prime is 642702653. The reversal of 642702649 is 946207246.

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

It can be written as a sum of positive squares in 2 ways, for example, as 364046400 + 278656249 = 19080^2 + 16693^2 .

It is a cyclic number.

It is not a de Polignac number, because 642702649 - 2¹ = 642702647 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642702647) 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, 5267994 + ... + 5268115.

It is an arithmetic number, because the mean of its divisors is an integer number (163309705).

Almost surely, 2^642702649 is an apocalyptic number.

It is an amenable number.

642702649 is a deficient number, since it is larger than the sum of its proper divisors (10536171).

642702649 is a wasteful number, since it uses less digits than its factorization.

642702649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10536170.

The product of its (nonzero) digits is 145152, while the sum is 40.

The square root of 642702649 is about 25351.5807988378. The cubic root of 642702649 is about 862.9852309621.

The spelling of 642702649 in words is "six hundred forty-two million, seven hundred two thousand, six hundred forty-nine".