20919553 has 4 divisors (see below), whose sum is σ = 21429828. Its totient is φ = 20409280.

The previous prime is 20919533. The next prime is 20919557. The reversal of 20919553 is 35591902.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5419584 + 15499969 = 2328^2 + 3937^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20919553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20919557) 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, 255076 + ... + 255157.

It is an arithmetic number, because the mean of its divisors is an integer number (5357457).

Almost surely, 2^20919553 is an apocalyptic number.

It is an amenable number.

20919553 is a deficient number, since it is larger than the sum of its proper divisors (510275).

20919553 is an equidigital number, since it uses as much as digits as its factorization.

20919553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 510274.

The product of its (nonzero) digits is 12150, while the sum is 34.

The square root of 20919553 is about 4573.7897852875. The cubic root of 20919553 is about 275.5396697169.

The spelling of 20919553 in words is "twenty million, nine hundred nineteen thousand, five hundred fifty-three".