660406402 has 4 divisors (see below), whose sum is σ = 990609606. Its totient is φ = 330203200.

The previous prime is 660406387. The next prime is 660406457. The reversal of 660406402 is 204604066.

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., 646125561 + 14280841 = 25419^2 + 3779^2 .

It is a super-2 number, since 2×660406402² = 872273231605171208, which contains 22 as substring.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 165101599 + ... + 165101602.

Almost surely, 2^660406402 is an apocalyptic number.

660406402 is a deficient number, since it is larger than the sum of its proper divisors (330203204).

660406402 is a wasteful number, since it uses less digits than its factorization.

660406402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330203203.

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 660406402 is about 25698.3735282994. The cubic root of 660406402 is about 870.8374382404.

The spelling of 660406402 in words is "six hundred sixty million, four hundred six thousand, four hundred two".