20819181 has 16 divisors (see below), whose sum is σ = 28582400. Its totient is φ = 13471920.

The previous prime is 20819173. The next prime is 20819213. The reversal of 20819181 is 18191802.

It is not a de Polignac number, because 20819181 - 2³ = 20819173 is a prime.

It is a super-2 number, since 2×20819181² = 866876595021522, 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 (20818181) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25266 + ... + 26076.

It is an arithmetic number, because the mean of its divisors is an integer number (1786400).

Almost surely, 2^20819181 is an apocalyptic number.

It is an amenable number.

20819181 is a deficient number, since it is larger than the sum of its proper divisors (7763219).

20819181 is a wasteful number, since it uses less digits than its factorization.

20819181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1056.

The product of its (nonzero) digits is 1152, while the sum is 30.

The square root of 20819181 is about 4562.8040720592. The cubic root of 20819181 is about 275.0982833273.

The spelling of 20819181 in words is "twenty million, eight hundred nineteen thousand, one hundred eighty-one".