6401655 has 48 divisors (see below), whose sum is σ = 12370176. Its totient is φ = 3041280.

The previous prime is 6401621. The next prime is 6401669. The reversal of 6401655 is 5561046.

It is a happy number.

6401655 is a `hidden beast` number, since 6 + 4 + 0 + 1 + 655 = 666.

It is not a de Polignac number, because 6401655 - 2⁸ = 6401399 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 17959 + ... + 18311.

It is an arithmetic number, because the mean of its divisors is an integer number (257712).

Almost surely, 2^6401655 is an apocalyptic number.

6401655 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

6401655 is a deficient number, since it is larger than the sum of its proper divisors (5968521).

6401655 is a wasteful number, since it uses less digits than its factorization.

6401655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 408 (or 405 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 6401655 is about 2530.1492050865. The cubic root of 6401655 is about 185.6795557767.

It can be divided in two parts, 6401 and 655, that added together give a square (7056 = 84²).

The spelling of 6401655 in words is "six million, four hundred one thousand, six hundred fifty-five".