642561326 has 16 divisors (see below), whose sum is σ = 1059747840. Its totient is φ = 289772280.

The previous prime is 642561319. The next prime is 642561329. The reversal of 642561326 is 623165246.

It is a happy number.

642561326 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642561329) 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, 112196 + ... + 117783.

It is an arithmetic number, because the mean of its divisors is an integer number (66234240).

Almost surely, 2^642561326 is an apocalyptic number.

642561326 is the 13550-th centered heptagonal number.

642561326 is a deficient number, since it is larger than the sum of its proper divisors (417186514).

642561326 is a wasteful number, since it uses less digits than its factorization.

642561326 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230119.

The product of its digits is 51840, while the sum is 35.

The square root of 642561326 is about 25348.7933835124. The cubic root of 642561326 is about 862.9219727808.

The spelling of 642561326 in words is "six hundred forty-two million, five hundred sixty-one thousand, three hundred twenty-six".