645335366563531 has 4 divisors (see below), whose sum is σ = 737526133215472. Its totient is φ = 553144599911592.

The previous prime is 645335366563457. The next prime is 645335366563543. The reversal of 645335366563531 is 135365663533546.

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 645335366563531 - 2¹⁷ = 645335366432459 is a prime.

It is a super-2 number, since 2×645335366563531² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645335366563031) 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, 46095383325960 + ... + 46095383325973.

It is an arithmetic number, because the mean of its divisors is an integer number (184381533303868).

Almost surely, 2^{645335366563531} is an apocalyptic number.

645335366563531 is a deficient number, since it is larger than the sum of its proper divisors (92190766651941).

645335366563531 is an equidigital number, since it uses as much as digits as its factorization.

645335366563531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92190766651940.

The product of its digits is 787320000, while the sum is 64.

The spelling of 645335366563531 in words is "six hundred forty-five trillion, three hundred thirty-five billion, three hundred sixty-six million, five hundred sixty-three thousand, five hundred thirty-one".