405242509 has 8 divisors (see below), whose sum is σ = 478074368. Its totient is φ = 336145680.

The previous prime is 405242477. The next prime is 405242527. The reversal of 405242509 is 905242504.

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

It is a cyclic number.

It is not a de Polignac number, because 405242509 - 2⁵ = 405242477 is a prime.

It is a super-2 number, since 2×405242509² = 328442982201230162, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405242809) 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, 933522 + ... + 933955.

It is an arithmetic number, because the mean of its divisors is an integer number (59759296).

Almost surely, 2^405242509 is an apocalyptic number.

It is an amenable number.

405242509 is a deficient number, since it is larger than the sum of its proper divisors (72831859).

405242509 is a wasteful number, since it uses less digits than its factorization.

405242509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1867515.

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 405242509 is about 20130.6360803627. The cubic root of 405242509 is about 740.0112665682.

The spelling of 405242509 in words is "four hundred five million, two hundred forty-two thousand, five hundred nine".