640105543610621 has 8 divisors (see below), whose sum is σ = 739373248234944. Its totient is φ = 547683887581120.

The previous prime is 640105543610609. The next prime is 640105543610641. The reversal of 640105543610621 is 126016345501046.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640105543610621 is a prime.

It is a super-2 number, since 2×640105543610621² (a number of 30 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 (640105543610641) 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, 1711512148505 + ... + 1711512148878.

It is an arithmetic number, because the mean of its divisors is an integer number (92421656029368).

Almost surely, 2^{640105543610621} is an apocalyptic number.

It is an amenable number.

640105543610621 is a deficient number, since it is larger than the sum of its proper divisors (99267704624323).

640105543610621 is a wasteful number, since it uses less digits than its factorization.

640105543610621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3423024297411.

The product of its (nonzero) digits is 518400, while the sum is 44.

The spelling of 640105543610621 in words is "six hundred forty trillion, one hundred five billion, five hundred forty-three million, six hundred ten thousand, six hundred twenty-one".