20813819 has 8 divisors (see below), whose sum is σ = 22474032. Its totient is φ = 19162080.

The previous prime is 20813813. The next prime is 20813839. The reversal of 20813819 is 91831802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20813819 - 2⁸ = 20813563 is a prime.

It is a super-2 number, since 2×20813819² = 866430122729522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20813813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3572 + ... + 7374.

It is an arithmetic number, because the mean of its divisors is an integer number (2809254).

Almost surely, 2^20813819 is an apocalyptic number.

20813819 is a deficient number, since it is larger than the sum of its proper divisors (1660213).

20813819 is a wasteful number, since it uses less digits than its factorization.

20813819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4237.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 20813819 is about 4562.2164569428. The cubic root of 20813819 is about 275.0746640240.

The spelling of 20813819 in words is "twenty million, eight hundred thirteen thousand, eight hundred nineteen".