405128917581 has 4 divisors (see below), whose sum is σ = 540171890112. Its totient is φ = 270085945052.

The previous prime is 405128917553. The next prime is 405128917597. The reversal of 405128917581 is 185719821504.

It is a happy number.

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 405128917581 - 2²³ = 405120528973 is a prime.

It is a super-2 number, since 2×405128917581² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405128917681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67521486261 + ... + 67521486266.

It is an arithmetic number, because the mean of its divisors is an integer number (135042972528).

Almost surely, 2^405128917581 is an apocalyptic number.

It is an amenable number.

405128917581 is a deficient number, since it is larger than the sum of its proper divisors (135042972531).

405128917581 is a wasteful number, since it uses less digits than its factorization.

405128917581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135042972530.

The product of its (nonzero) digits is 806400, while the sum is 51.

The spelling of 405128917581 in words is "four hundred five billion, one hundred twenty-eight million, nine hundred seventeen thousand, five hundred eighty-one".