642515421 has 16 divisors (see below), whose sum is σ = 861324480. Its totient is φ = 426032640.

The previous prime is 642515389. The next prime is 642515473. The reversal of 642515421 is 124515246.

It is not a de Polignac number, because 642515421 - 2⁵ = 642515389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642515491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 782191 + ... + 783011.

It is an arithmetic number, because the mean of its divisors is an integer number (53832780).

Almost surely, 2^642515421 is an apocalyptic number.

It is an amenable number.

642515421 is a deficient number, since it is larger than the sum of its proper divisors (218809059).

642515421 is a wasteful number, since it uses less digits than its factorization.

642515421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1916.

The product of its digits is 9600, while the sum is 30.

The square root of 642515421 is about 25347.8879001782. The cubic root of 642515421 is about 862.9014230554.

The spelling of 642515421 in words is "six hundred forty-two million, five hundred fifteen thousand, four hundred twenty-one".