403281661 has 4 divisors (see below), whose sum is σ = 405850492. Its totient is φ = 400712832.

The previous prime is 403281607. The next prime is 403281677. The reversal of 403281661 is 166182304.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 139381636 + 263900025 = 11806^2 + 16245^2 .

It is a cyclic number.

It is not a de Polignac number, because 403281661 - 2⁷ = 403281533 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 (403281691) 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, 1284180 + ... + 1284493.

It is an arithmetic number, because the mean of its divisors is an integer number (101462623).

Almost surely, 2^403281661 is an apocalyptic number.

It is an amenable number.

403281661 is a deficient number, since it is larger than the sum of its proper divisors (2568831).

403281661 is a wasteful number, since it uses less digits than its factorization.

403281661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2568830.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 403281661 is about 20081.8739414428. The cubic root of 403281661 is about 738.8157714505.

The spelling of 403281661 in words is "four hundred three million, two hundred eighty-one thousand, six hundred sixty-one".