645740564247936 has 768 divisors, whose sum is σ = 2130625435760640. Its totient is φ = 193635854843904.

The previous prime is 645740564247901. The next prime is 645740564248033. The reversal of 645740564247936 is 639742465047546.

645740564247936 is a `hidden beast` number, since 6 + 4 + 5 + 7 + 4 + 0 + 564 + 24 + 7 + 9 + 36 = 666.

It is a super-2 number, since 2×645740564247936² (a number of 30 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 17306029216 + ... + 17306066528.

It is an arithmetic number, because the mean of its divisors is an integer number (2774251869480).

Almost surely, 2^{645740564247936} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645740564247936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1065312717880320).

645740564247936 is an abundant number, since it is smaller than the sum of its proper divisors (1484884871512704).

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

645740564247936 is a wasteful number, since it uses less digits than its factorization.

645740564247936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38805 (or 38781 counting only the distinct ones).

The product of its (nonzero) digits is 3657830400, while the sum is 72.

The spelling of 645740564247936 in words is "six hundred forty-five trillion, seven hundred forty billion, five hundred sixty-four million, two hundred forty-seven thousand, nine hundred thirty-six".