401856665 has 8 divisors (see below), whose sum is σ = 551117760. Its totient is φ = 275558832.

The previous prime is 401856643. The next prime is 401856677. The reversal of 401856665 is 566658104.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 401856665 - 2⁸ = 401856409 is a prime.

It is a super-2 number, since 2×401856665² = 322977558409844450, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5740775 + ... + 5740844.

It is an arithmetic number, because the mean of its divisors is an integer number (68889720).

Almost surely, 2^401856665 is an apocalyptic number.

It is an amenable number.

401856665 is a deficient number, since it is larger than the sum of its proper divisors (149261095).

401856665 is a wasteful number, since it uses less digits than its factorization.

401856665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11481631.

The product of its (nonzero) digits is 172800, while the sum is 41.

The square root of 401856665 is about 20046.3628870676. The cubic root of 401856665 is about 737.9445424846.

The spelling of 401856665 in words is "four hundred one million, eight hundred fifty-six thousand, six hundred sixty-five".