405021217 has 4 divisors (see below), whose sum is σ = 405387540. Its totient is φ = 404654896.

The previous prime is 405021193. The next prime is 405021241. The reversal of 405021217 is 712120504.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (405021193) and next prime (405021241).

It can be written as a sum of positive squares in 2 ways, for example, as 192765456 + 212255761 = 13884^2 + 14569^2 .

It is a cyclic number.

It is not a de Polignac number, because 405021217 - 2²³ = 396632609 is a prime.

It is a super-2 number, since 2×405021217² = 328084372440322178, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (405121217) 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, 181498 + ... + 183715.

It is an arithmetic number, because the mean of its divisors is an integer number (101346885).

Almost surely, 2^405021217 is an apocalyptic number.

It is an amenable number.

405021217 is a deficient number, since it is larger than the sum of its proper divisors (366323).

405021217 is a wasteful number, since it uses less digits than its factorization.

405021217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366322.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 405021217 is about 20125.1389311975. The cubic root of 405021217 is about 739.8765419801.

The spelling of 405021217 in words is "four hundred five million, twenty-one thousand, two hundred seventeen".