402565551491 has 2 divisors, whose sum is σ = 402565551492. Its totient is φ = 402565551490.

The previous prime is 402565551473. The next prime is 402565551551. The reversal of 402565551491 is 194155565204.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 402565551491 - 2¹⁰ = 402565550467 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (402565551391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201282775745 + 201282775746.

It is an arithmetic number, because the mean of its divisors is an integer number (201282775746).

Almost surely, 2^402565551491 is an apocalyptic number.

402565551491 is a deficient number, since it is larger than the sum of its proper divisors (1).

402565551491 is an equidigital number, since it uses as much as digits as its factorization.

402565551491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080000, while the sum is 47.

The spelling of 402565551491 in words is "four hundred two billion, five hundred sixty-five million, five hundred fifty-one thousand, four hundred ninety-one".