405901609 has 3 divisors (see below), whose sum is σ = 405921757. Its totient is φ = 405881462.

The previous prime is 405901591. The next prime is 405901621. The reversal of 405901609 is 906109504.

The square root of 405901609 is 20147.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 405901609 - 2⁷ = 405901481 is a prime.

It is a super-2 number, since 2×405901609² = 329512232377577762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (405901649) 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 2 ways as a sum of consecutive naturals, for example, 10074 + ... + 30220.

Almost surely, 2^405901609 is an apocalyptic number.

405901609 is the 20147-th square number.

405901609 is the 10074-th centered octagonal number.

It is an amenable number.

405901609 is a deficient number, since it is larger than the sum of its proper divisors (20148).

405901609 is an frugal number, since it uses more digits than its factorization.

405901609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40294 (or 20147 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 34.

The cubic root of 405901609 is about 740.4122423027.

The spelling of 405901609 in words is "four hundred five million, nine hundred one thousand, six hundred nine".