645711023640 has 64 divisors (see below), whose sum is σ = 1937255522400. Its totient is φ = 172178721792.

The previous prime is 645711023627. The next prime is 645711023677. The reversal of 645711023640 is 46320117546.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1834206 + ... + 2157714.

Almost surely, 2^645711023640 is an apocalyptic number.

645711023640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

645711023640 is an abundant number, since it is smaller than the sum of its proper divisors (1291544498760).

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

645711023640 is a wasteful number, since it uses less digits than its factorization.

645711023640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340156 (or 340152 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 39.

The spelling of 645711023640 in words is "six hundred forty-five billion, seven hundred eleven million, twenty-three thousand, six hundred forty".