642165626 has 4 divisors (see below), whose sum is σ = 963248442. Its totient is φ = 321082812.

The previous prime is 642165611. The next prime is 642165631. The reversal of 642165626 is 626561246.

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

It can be written as a sum of positive squares in only one way, i.e., 554649601 + 87516025 = 23551^2 + 9355^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 642165626.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160541405 + ... + 160541408.

Almost surely, 2^642165626 is an apocalyptic number.

642165626 is a deficient number, since it is larger than the sum of its proper divisors (321082816).

642165626 is a wasteful number, since it uses less digits than its factorization.

642165626 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321082815.

The product of its digits is 103680, while the sum is 38.

The square root of 642165626 is about 25340.9870762763. The cubic root of 642165626 is about 862.7448024851.

The spelling of 642165626 in words is "six hundred forty-two million, one hundred sixty-five thousand, six hundred twenty-six".