405905978 has 8 divisors (see below), whose sum is σ = 635331168. Its totient is φ = 194128924.

The previous prime is 405905977. The next prime is 405905999. The reversal of 405905978 is 879509504.

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

It is a super-2 number, since 2×405905978² = 329519325952272968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (405905977) 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, 4411976 + ... + 4412067.

It is an arithmetic number, because the mean of its divisors is an integer number (79416396).

Almost surely, 2^405905978 is an apocalyptic number.

405905978 is a deficient number, since it is larger than the sum of its proper divisors (229425190).

405905978 is a wasteful number, since it uses less digits than its factorization.

405905978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8824068.

The product of its (nonzero) digits is 453600, while the sum is 47.

The square root of 405905978 is about 20147.1084277620. The cubic root of 405905978 is about 740.4148988163.

The spelling of 405905978 in words is "four hundred five million, nine hundred five thousand, nine hundred seventy-eight".