402661621 has 4 divisors (see below), whose sum is σ = 420168672. Its totient is φ = 385154572.

The previous prime is 402661619. The next prime is 402661663. The reversal of 402661621 is 126166204.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 402661621 - 2¹ = 402661619 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 402661621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402661681) 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, 8753491 + ... + 8753536.

It is an arithmetic number, because the mean of its divisors is an integer number (105042168).

Almost surely, 2^402661621 is an apocalyptic number.

It is an amenable number.

402661621 is a deficient number, since it is larger than the sum of its proper divisors (17507051).

402661621 is a wasteful number, since it uses less digits than its factorization.

402661621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17507050.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 402661621 is about 20066.4302007108. The cubic root of 402661621 is about 738.4369375421.

The spelling of 402661621 in words is "four hundred two million, six hundred sixty-one thousand, six hundred twenty-one".