6397990 has 16 divisors (see below), whose sum is σ = 11566800. Its totient is φ = 2548000.

The previous prime is 6397981. The next prime is 6397991. The reversal of 6397990 is 997936.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6397991) 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, 1236 + ... + 3784.

It is an arithmetic number, because the mean of its divisors is an integer number (722925).

Almost surely, 2^6397990 is an apocalyptic number.

6397990 is a deficient number, since it is larger than the sum of its proper divisors (5168810).

6397990 is a wasteful number, since it uses less digits than its factorization.

6397990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2807.

The product of its (nonzero) digits is 91854, while the sum is 43.

The square root of 6397990 is about 2529.4248358075. The cubic root of 6397990 is about 185.6441146561.

It can be divided in two parts, 639 and 7990, that multiplied together give a triangular number (5105610 = T₃₁₉₅).

The spelling of 6397990 in words is "six million, three hundred ninety-seven thousand, nine hundred ninety".