402778 has 4 divisors (see below), whose sum is σ = 604170. Its totient is φ = 201388.

The previous prime is 402769. The next prime is 402797. The reversal of 402778 is 877204.

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

It can be written as a sum of positive squares in only one way, i.e., 253009 + 149769 = 503^2 + 387^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100693 + ... + 100696.

2⁴⁰²⁷⁷⁸ is an apocalyptic number.

402778 is a deficient number, since it is larger than the sum of its proper divisors (201392).

402778 is a wasteful number, since it uses less digits than its factorization.

402778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201391.

The product of its (nonzero) digits is 3136, while the sum is 28.

The square root of 402778 is about 634.6479338972. The cubic root of 402778 is about 73.8508072766.

The spelling of 402778 in words is "four hundred two thousand, seven hundred seventy-eight".