20215919 has 4 divisors (see below), whose sum is σ = 21094896. Its totient is φ = 19336944.

The previous prime is 20215883. The next prime is 20215967. The reversal of 20215919 is 91951202.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20215919 is a prime.

It is a super-2 number, since 2×20215919² = 817366762029122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20215891 and 20215900.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20215319) 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, 439454 + ... + 439499.

It is an arithmetic number, because the mean of its divisors is an integer number (5273724).

Almost surely, 2^20215919 is an apocalyptic number.

20215919 is a deficient number, since it is larger than the sum of its proper divisors (878977).

20215919 is an equidigital number, since it uses as much as digits as its factorization.

20215919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878976.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 20215919 is about 4496.2116275816. The cubic root of 20215919 is about 272.4150912408.

The spelling of 20215919 in words is "twenty million, two hundred fifteen thousand, nine hundred nineteen".