6421690 has 16 divisors (see below), whose sum is σ = 12610080. Its totient is φ = 2335120.

The previous prime is 6421643. The next prime is 6421697. The reversal of 6421690 is 961246.

It is a super-2 number, since 2×6421690² = 82476204912200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6421697) 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, 29080 + ... + 29299.

It is an arithmetic number, because the mean of its divisors is an integer number (788130).

Almost surely, 2^6421690 is an apocalyptic number.

6421690 is a deficient number, since it is larger than the sum of its proper divisors (6188390).

6421690 is a wasteful number, since it uses less digits than its factorization.

6421690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58397.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 6421690 is about 2534.1053648181. The cubic root of 6421690 is about 185.8730586424.

It can be divided in two parts, 642 and 1690, that added together give a palindrome (2332).

The spelling of 6421690 in words is "six million, four hundred twenty-one thousand, six hundred ninety".