402861991 has 4 divisors (see below), whose sum is σ = 460413712. Its totient is φ = 345310272.

The previous prime is 402861989. The next prime is 402862003. The reversal of 402861991 is 199168204.

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 402861991 - 2¹ = 402861989 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 (402861391) 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, 28775850 + ... + 28775863.

It is an arithmetic number, because the mean of its divisors is an integer number (115103428).

Almost surely, 2^402861991 is an apocalyptic number.

402861991 is a deficient number, since it is larger than the sum of its proper divisors (57551721).

402861991 is an equidigital number, since it uses as much as digits as its factorization.

402861991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57551720.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 402861991 is about 20071.4222465674. The cubic root of 402861991 is about 738.5594027137.

The spelling of 402861991 in words is "four hundred two million, eight hundred sixty-one thousand, nine hundred ninety-one".