20878997 has 4 divisors (see below), whose sum is σ = 20936256. Its totient is φ = 20821740.

The previous prime is 20878987. The next prime is 20878999. The reversal of 20878997 is 79987802.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 20878997 - 2⁴ = 20878981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20878999) 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, 28079 + ... + 28812.

It is an arithmetic number, because the mean of its divisors is an integer number (5234064).

Almost surely, 2^20878997 is an apocalyptic number.

It is an amenable number.

20878997 is a deficient number, since it is larger than the sum of its proper divisors (57259).

20878997 is an equidigital number, since it uses as much as digits as its factorization.

20878997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57258.

The product of its (nonzero) digits is 508032, while the sum is 50.

The square root of 20878997 is about 4569.3541119068. The cubic root of 20878997 is about 275.3614948451.

The spelling of 20878997 in words is "twenty million, eight hundred seventy-eight thousand, nine hundred ninety-seven".