20881945 has 16 divisors (see below), whose sum is σ = 28764288. Its totient is φ = 14256000.

The previous prime is 20881921. The next prime is 20881963. The reversal of 20881945 is 54918802.

It is not a de Polignac number, because 20881945 - 2⁹ = 20881433 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7597 + ... + 9973.

It is an arithmetic number, because the mean of its divisors is an integer number (1797768).

Almost surely, 2^20881945 is an apocalyptic number.

It is an amenable number.

20881945 is a deficient number, since it is larger than the sum of its proper divisors (7882343).

20881945 is a wasteful number, since it uses less digits than its factorization.

20881945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2640.

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 20881945 is about 4569.6766844056. The cubic root of 20881945 is about 275.3744540801.

The spelling of 20881945 in words is "twenty million, eight hundred eighty-one thousand, nine hundred forty-five".