20878493 has 4 divisors (see below), whose sum is σ = 20887680. Its totient is φ = 20869308.

The previous prime is 20878477. The next prime is 20878513. The reversal of 20878493 is 39487802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20878493 - 2⁴ = 20878477 is a prime.

It is a super-2 number, since 2×20878493² = 871822939902098, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20878493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20878433) 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, 1598 + ... + 6656.

It is an arithmetic number, because the mean of its divisors is an integer number (5221920).

Almost surely, 2^20878493 is an apocalyptic number.

It is an amenable number.

20878493 is a deficient number, since it is larger than the sum of its proper divisors (9187).

20878493 is an equidigital number, since it uses as much as digits as its factorization.

20878493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9186.

The product of its (nonzero) digits is 96768, while the sum is 41.

The square root of 20878493 is about 4569.2989615476. The cubic root of 20878493 is about 275.3592791686.

The spelling of 20878493 in words is "twenty million, eight hundred seventy-eight thousand, four hundred ninety-three".