20919885 has 32 divisors (see below), whose sum is σ = 39493632. Its totient is φ = 9253440.

The previous prime is 20919883. The next prime is 20919919. The reversal of 20919885 is 58891902.

It is a happy number.

It is not a de Polignac number, because 20919885 - 2¹ = 20919883 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20919883) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42 + ... + 6468.

It is an arithmetic number, because the mean of its divisors is an integer number (1234176).

Almost surely, 2^20919885 is an apocalyptic number.

It is an amenable number.

20919885 is a deficient number, since it is larger than the sum of its proper divisors (18573747).

20919885 is a wasteful number, since it uses less digits than its factorization.

20919885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6473.

The product of its (nonzero) digits is 51840, while the sum is 42.

The square root of 20919885 is about 4573.8260788972. The cubic root of 20919885 is about 275.5411273434.

The spelling of 20919885 in words is "twenty million, nine hundred nineteen thousand, eight hundred eighty-five".