645762206435551 has 4 divisors (see below), whose sum is σ = 645766514222704. Its totient is φ = 645757898648400.

The previous prime is 645762206435519. The next prime is 645762206435651. The reversal of 645762206435551 is 155534602267546.

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

It is a cyclic number.

It is not a de Polignac number, because 645762206435551 - 2⁵ = 645762206435519 is a prime.

It is a super-2 number, since 2×645762206435551² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645762206435551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645762206435251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2153668710 + ... + 2153968531.

It is an arithmetic number, because the mean of its divisors is an integer number (161441628555676).

Almost surely, 2^{645762206435551} is an apocalyptic number.

645762206435551 is a deficient number, since it is larger than the sum of its proper divisors (4307787153).

645762206435551 is a wasteful number, since it uses less digits than its factorization.

645762206435551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4307787152.

The product of its (nonzero) digits is 181440000, while the sum is 61.

The spelling of 645762206435551 in words is "six hundred forty-five trillion, seven hundred sixty-two billion, two hundred six million, four hundred thirty-five thousand, five hundred fifty-one".