642565766404 has 27 divisors (see below), whose sum is σ = 1128174652647. Its totient is φ = 320233586184.

The previous prime is 642565766383. The next prime is 642565766411. The reversal of 642565766404 is 404667565246.

The square root of 642565766404 is 801602.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 780759937 + ... + 780760759.

Almost surely, 2^642565766404 is an apocalyptic number.

642565766404 is the 801602-nd square number.

It is an amenable number.

642565766404 is a deficient number, since it is larger than the sum of its proper divisors (485608886243).

642565766404 is an frugal number, since it uses more digits than its factorization.

642565766404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2624 (or 1312 counting only the distinct ones).

The product of its (nonzero) digits is 29030400, while the sum is 55.

It can be divided in two parts, 642565 and 766404, that added together give a square (1408969 = 1187²).

The spelling of 642565766404 in words is "six hundred forty-two billion, five hundred sixty-five million, seven hundred sixty-six thousand, four hundred four".