6438621690 has 32 divisors (see below), whose sum is σ = 17169658560. Its totient is φ = 1716965712.

The previous prime is 6438621661. The next prime is 6438621703. The reversal of 6438621690 is 961268346.

It is a super-2 number, since 2×6438621690² = 82911698533876912200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11923104 + ... + 11923643.

It is an arithmetic number, because the mean of its divisors is an integer number (536551830).

Almost surely, 2^6438621690 is an apocalyptic number.

6438621690 is an abundant number, since it is smaller than the sum of its proper divisors (10731036870).

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

6438621690 is a wasteful number, since it uses less digits than its factorization.

6438621690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23846763 (or 23846757 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 6438621690 is about 80241.0224885002. The cubic root of 6438621690 is about 1860.3627544298.

The spelling of 6438621690 in words is "six billion, four hundred thirty-eight million, six hundred twenty-one thousand, six hundred ninety".