400515551 has 2 divisors, whose sum is σ = 400515552. Its totient is φ = 400515550.

The previous prime is 400515523. The next prime is 400515637. The reversal of 400515551 is 155515004.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 400515551 - 2¹⁸ = 400253407 is a prime.

It is a Chen prime.

It is equal to p_21362309 and since 400515551 and 21362309 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 400515551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400515251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200257775 + 200257776.

It is an arithmetic number, because the mean of its divisors is an integer number (200257776).

Almost surely, 2^400515551 is an apocalyptic number.

400515551 is a deficient number, since it is larger than the sum of its proper divisors (1).

400515551 is an equidigital number, since it uses as much as digits as its factorization.

400515551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2500, while the sum is 26.

The square root of 400515551 is about 20012.8846246612. The cubic root of 400515551 is about 737.1227148474.

The spelling of 400515551 in words is "four hundred million, five hundred fifteen thousand, five hundred fifty-one".