400644263 has 4 divisors (see below), whose sum is σ = 400686480. Its totient is φ = 400602048.

The previous prime is 400644247. The next prime is 400644271. The reversal of 400644263 is 362446004.

It is a happy number.

It is a semiprime because it is the product of two primes, 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 400644263 - 2⁴ = 400644247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400643263) 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, 503 + ... + 28311.

It is an arithmetic number, because the mean of its divisors is an integer number (100171620).

Almost surely, 2^400644263 is an apocalyptic number.

400644263 is a deficient number, since it is larger than the sum of its proper divisors (42217).

400644263 is a wasteful number, since it uses less digits than its factorization.

400644263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42216.

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 400644263 is about 20016.1000946738. The cubic root of 400644263 is about 737.2016684004.

The spelling of 400644263 in words is "four hundred million, six hundred forty-four thousand, two hundred sixty-three".