6401990 has 16 divisors (see below), whose sum is σ = 13169952. Its totient is φ = 2194944.

The previous prime is 6401987. The next prime is 6402001. The reversal of 6401990 is 991046.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45659 + ... + 45798.

It is an arithmetic number, because the mean of its divisors is an integer number (823122).

Almost surely, 2^6401990 is an apocalyptic number.

6401990 is an abundant number, since it is smaller than the sum of its proper divisors (6767962).

6401990 is a wasteful number, since it uses less digits than its factorization.

6401990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91471.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 6401990 is about 2530.2154058499. The cubic root of 6401990 is about 185.6827946041.

Subtracting from 6401990 its product of nonzero digits (1944), we obtain a palindrome (6400046).

The spelling of 6401990 in words is "six million, four hundred one thousand, nine hundred ninety".