402756021 has 12 divisors (see below), whose sum is σ = 582135372. Its totient is φ = 268330176.

The previous prime is 402756001. The next prime is 402756023. The reversal of 402756021 is 120657204.

It can be written as a sum of positive squares in 2 ways, for example, as 185340996 + 217415025 = 13614^2 + 14745^2 .

It is not a de Polignac number, because 402756021 - 2¹¹ = 402753973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402756023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1065 + ... + 28401.

It is an arithmetic number, because the mean of its divisors is an integer number (48511281).

Almost surely, 2^402756021 is an apocalyptic number.

It is an amenable number.

402756021 is a deficient number, since it is larger than the sum of its proper divisors (179379351).

402756021 is a wasteful number, since it uses less digits than its factorization.

402756021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28980 (or 28977 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 402756021 is about 20068.7822500519. The cubic root of 402756021 is about 738.4946394242.

The spelling of 402756021 in words is "four hundred two million, seven hundred fifty-six thousand, twenty-one".