645742026720 has 384 divisors, whose sum is σ = 2585810304000. Its totient is φ = 147435780096.

The previous prime is 645742026719. The next prime is 645742026793. The reversal of 645742026720 is 27620247546.

It is a happy number.

645742026720 is a `hidden beast` number, since 6 + 4 + 574 + 2 + 0 + 2 + 6 + 72 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 28626006 + ... + 28648554.

It is an arithmetic number, because the mean of its divisors is an integer number (6733881000).

Almost surely, 2^645742026720 is an apocalyptic number.

645742026720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645742026720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1292905152000).

645742026720 is an abundant number, since it is smaller than the sum of its proper divisors (1940068277280).

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

645742026720 is a wasteful number, since it uses less digits than its factorization.

645742026720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23527 (or 23513 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 45.

The spelling of 645742026720 in words is "six hundred forty-five billion, seven hundred forty-two million, twenty-six thousand, seven hundred twenty".