645312213546 has 256 divisors, whose sum is σ = 1749362614272. Its totient is φ = 153254476800.

The previous prime is 645312213523. The next prime is 645312213551.

645312213546 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 645312213498 and 645312213507.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 323139820 + ... + 323141816.

It is an arithmetic number, because the mean of its divisors is an integer number (6833447712).

Almost surely, 2^645312213546 is an apocalyptic number.

645312213546 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 645312213546, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (874681307136).

645312213546 is an abundant number, since it is smaller than the sum of its proper divisors (1104050400726).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645312213546 is a wasteful number, since it uses less digits than its factorization.

645312213546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2517.

The product of its digits is 518400, while the sum is 42.

It can be divided in two parts, 645312 and 213546, that added together give a palindrome (858858).

The spelling of 645312213546 in words is "six hundred forty-five billion, three hundred twelve million, two hundred thirteen thousand, five hundred forty-six".