640477231837 has 8 divisors (see below), whose sum is σ = 642156442200. Its totient is φ = 638798190144.

The previous prime is 640477231789. The next prime is 640477231861. The reversal of 640477231837 is 738132774046.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20343031641 + 620134200196 = 142629^2 + 787486^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640477231837 - 2¹¹ = 640477229789 is a prime.

It is a super-2 number, since 2×640477231837² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640477231637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12124839 + ... + 12177547.

It is an arithmetic number, because the mean of its divisors is an integer number (80269555275).

Almost surely, 2^640477231837 is an apocalyptic number.

It is an amenable number.

640477231837 is a deficient number, since it is larger than the sum of its proper divisors (1679210363).

640477231837 is a wasteful number, since it uses less digits than its factorization.

640477231837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84335.

The product of its (nonzero) digits is 4741632, while the sum is 52.

The spelling of 640477231837 in words is "six hundred forty billion, four hundred seventy-seven million, two hundred thirty-one thousand, eight hundred thirty-seven".