6401988 has 36 divisors (see below), whose sum is σ = 16297008. Its totient is φ = 2118960.

The previous prime is 6401987. The next prime is 6402001. The reversal of 6401988 is 8891046.

It is a happy number.

6401988 is a `hidden beast` number, since 640 + 1 + 9 + 8 + 8 = 666.

6401988 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (6401987) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5323 + ... + 6413.

Almost surely, 2^6401988 is an apocalyptic number.

It is an amenable number.

6401988 is an abundant number, since it is smaller than the sum of its proper divisors (9895020).

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

6401988 is a wasteful number, since it uses less digits than its factorization.

6401988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1264 (or 1259 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 6401988 is about 2530.2150106266. The cubic root of 6401988 is about 185.6827752681.

It can be divided in two parts, 640 and 1988, that added together give a triangular number (2628 = T₇₂).

The spelling of 6401988 in words is "six million, four hundred one thousand, nine hundred eighty-eight".