402581661 has 8 divisors (see below), whose sum is σ = 538915104. Its totient is φ = 267318000.

The previous prime is 402581659. The next prime is 402581681. The reversal of 402581661 is 166185204.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 402581661 - 2¹ = 402581659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402581651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 266566 + ... + 268071.

It is an arithmetic number, because the mean of its divisors is an integer number (67364388).

Almost surely, 2^402581661 is an apocalyptic number.

It is an amenable number.

402581661 is a deficient number, since it is larger than the sum of its proper divisors (136333443).

402581661 is a wasteful number, since it uses less digits than its factorization.

402581661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534891.

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 402581661 is about 20064.4377195076. The cubic root of 402581661 is about 738.3880550369.

The spelling of 402581661 in words is "four hundred two million, five hundred eighty-one thousand, six hundred sixty-one".