400551 has 16 divisors (see below), whose sum is σ = 568320. Its totient is φ = 250560.

The previous prime is 400523. The next prime is 400559. The reversal of 400551 is 155004.

It is not a de Polignac number, because 400551 - 2¹⁰ = 399527 is a prime.

It is a super-2 number, since 2×400551² = 320882207202, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 400551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400559) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5451 + ... + 5523.

It is an arithmetic number, because the mean of its divisors is an integer number (35520).

2⁴⁰⁰⁵⁵¹ is an apocalyptic number.

400551 is a deficient number, since it is larger than the sum of its proper divisors (167769).

400551 is a wasteful number, since it uses less digits than its factorization.

400551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166.

The product of its (nonzero) digits is 100, while the sum is 15.

The square root of 400551 is about 632.8909858736. The cubic root of 400551 is about 73.7144461396.

Adding to 400551 its reverse (155004), we get a palindrome (555555).

The spelling of 400551 in words is "four hundred thousand, five hundred fifty-one".