400457391 has 4 divisors (see below), whose sum is σ = 533943192. Its totient is φ = 266971592.

The previous prime is 400457377. The next prime is 400457413. The reversal of 400457391 is 193754004.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 400457391 - 2¹⁰ = 400456367 is a prime.

It is a super-2 number, since 2×400457391² = 320732244013053762, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400457311) 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, 66742896 + ... + 66742901.

It is an arithmetic number, because the mean of its divisors is an integer number (133485798).

Almost surely, 2^400457391 is an apocalyptic number.

400457391 is a deficient number, since it is larger than the sum of its proper divisors (133485801).

400457391 is a wasteful number, since it uses less digits than its factorization.

400457391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133485800.

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 400457391 is about 20011.4315080156. The cubic root of 400457391 is about 737.0870332263.

The spelling of 400457391 in words is "four hundred million, four hundred fifty-seven thousand, three hundred ninety-one".