405711981 has 6 divisors (see below), whose sum is σ = 586028430. Its totient is φ = 270474648.

The previous prime is 405711931. The next prime is 405711983. The reversal of 405711981 is 189117504.

405711981 is a `hidden beast` number, since 4 + 0 + 571 + 1 + 9 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 389430756 + 16281225 = 19734^2 + 4035^2 .

It is not a de Polignac number, because 405711981 - 2⁷ = 405711853 is a prime.

It is a super-2 number, since 2×405711981² = 329204423053888722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405711983) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 22539546 + ... + 22539563.

It is an arithmetic number, because the mean of its divisors is an integer number (97671405).

Almost surely, 2^405711981 is an apocalyptic number.

It is an amenable number.

405711981 is a deficient number, since it is larger than the sum of its proper divisors (180316449).

405711981 is a wasteful number, since it uses less digits than its factorization.

405711981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45079115 (or 45079112 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 36.

The square root of 405711981 is about 20142.2933401338. The cubic root of 405711981 is about 740.2969230894.

The spelling of 405711981 in words is "four hundred five million, seven hundred eleven thousand, nine hundred eighty-one".