640731447140 has 24 divisors (see below), whose sum is σ = 1354106338872. Its totient is φ = 254660140800.

The previous prime is 640731447137. The next prime is 640731447197. The reversal of 640731447140 is 41744137046.

It can be written as a sum of positive squares in 4 ways, for example, as 9304145764 + 631427301376 = 96458^2 + 794624^2 .

It is a super-2 number, since 2×640731447140² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102024161 + ... + 102030440.

It is an arithmetic number, because the mean of its divisors is an integer number (56421097453).

Almost surely, 2^640731447140 is an apocalyptic number.

It is an amenable number.

640731447140 is an abundant number, since it is smaller than the sum of its proper divisors (713374891732).

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

640731447140 is a wasteful number, since it uses less digits than its factorization.

640731447140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204054767 (or 204054765 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 41.

The spelling of 640731447140 in words is "six hundred forty billion, seven hundred thirty-one million, four hundred forty-seven thousand, one hundred forty".