20901919 has 4 divisors (see below), whose sum is σ = 22002040. Its totient is φ = 19801800.

The previous prime is 20901911. The next prime is 20901931. The reversal of 20901919 is 91910902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91910902 = 2 ⋅45955451.

It is not a de Polignac number, because 20901919 - 2³ = 20901911 is a prime.

It is a super-2 number, since 2×20901919² = 873780435765122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20901911) 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, 550032 + ... + 550069.

It is an arithmetic number, because the mean of its divisors is an integer number (5500510).

Almost surely, 2^20901919 is an apocalyptic number.

20901919 is a deficient number, since it is larger than the sum of its proper divisors (1100121).

20901919 is a wasteful number, since it uses less digits than its factorization.

20901919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100120.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 20901919 is about 4571.8616558247. The cubic root of 20901919 is about 275.4622265002.

The spelling of 20901919 in words is "twenty million, nine hundred one thousand, nine hundred nineteen".