20901869 has 4 divisors (see below), whose sum is σ = 21042300. Its totient is φ = 20761440.

The previous prime is 20901863. The next prime is 20901889. The reversal of 20901869 is 96810902.

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 9375844 + 11526025 = 3062^2 + 3395^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20901869 is a prime.

It is a super-2 number, since 2×20901869² = 873776255386322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20901863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69992 + ... + 70289.

It is an arithmetic number, because the mean of its divisors is an integer number (5260575).

Almost surely, 2^20901869 is an apocalyptic number.

It is an amenable number.

20901869 is a deficient number, since it is larger than the sum of its proper divisors (140431).

20901869 is a wasteful number, since it uses less digits than its factorization.

20901869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140430.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 20901869 is about 4571.8561875895. The cubic root of 20901869 is about 275.4620068534.

The spelling of 20901869 in words is "twenty million, nine hundred one thousand, eight hundred sixty-nine".