401662561 has 4 divisors (see below), whose sum is σ = 401703472. Its totient is φ = 401621652.

The previous prime is 401662537. The next prime is 401662627. The reversal of 401662561 is 165266104.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 401662561 - 2⁷ = 401662433 is a prime.

It is a super-2 number, since 2×401662561² = 322665625818157442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (401662531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4090 + ... + 28636.

It is an arithmetic number, because the mean of its divisors is an integer number (100425868).

Almost surely, 2^401662561 is an apocalyptic number.

It is an amenable number.

401662561 is a deficient number, since it is larger than the sum of its proper divisors (40911).

401662561 is a wasteful number, since it uses less digits than its factorization.

401662561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40910.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 401662561 is about 20041.5209253190. The cubic root of 401662561 is about 737.8257098524.

The spelling of 401662561 in words is "four hundred one million, six hundred sixty-two thousand, five hundred sixty-one".