641355251621 has 16 divisors (see below), whose sum is σ = 771602841600. Its totient is φ = 520767588528.

The previous prime is 641355251617. The next prime is 641355251731. The reversal of 641355251621 is 126152553146.

It is a cyclic number.

It is not a de Polignac number, because 641355251621 - 2² = 641355251617 is a prime.

It is a super-2 number, since 2×641355251621² (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 (641355251611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2145020 + ... + 2425658.

It is an arithmetic number, because the mean of its divisors is an integer number (48225177600).

Almost surely, 2^641355251621 is an apocalyptic number.

It is an amenable number.

641355251621 is a deficient number, since it is larger than the sum of its proper divisors (130247589979).

641355251621 is a wasteful number, since it uses less digits than its factorization.

641355251621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297848.

The product of its digits is 216000, while the sum is 41.

The spelling of 641355251621 in words is "six hundred forty-one billion, three hundred fifty-five million, two hundred fifty-one thousand, six hundred twenty-one".