20406945 has 16 divisors (see below), whose sum is σ = 35163072. Its totient is φ = 10046400.

The previous prime is 20406941. The next prime is 20406973. The reversal of 20406945 is 54960402.

It is not a de Polignac number, because 20406945 - 2² = 20406941 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20406941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52131 + ... + 52520.

It is an arithmetic number, because the mean of its divisors is an integer number (2197692).

Almost surely, 2^20406945 is an apocalyptic number.

It is an amenable number.

20406945 is a deficient number, since it is larger than the sum of its proper divisors (14756127).

20406945 is a wasteful number, since it uses less digits than its factorization.

20406945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104672.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 20406945 is about 4517.4046752533. The cubic root of 20406945 is about 273.2704454104.

The spelling of 20406945 in words is "twenty million, four hundred six thousand, nine hundred forty-five".