20720878 has 4 divisors (see below), whose sum is σ = 31081320. Its totient is φ = 10360438.

The previous prime is 20720789. The next prime is 20720893. The reversal of 20720878 is 87802702.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5180218 + ... + 5180221.

It is an arithmetic number, because the mean of its divisors is an integer number (7770330).

Almost surely, 2^20720878 is an apocalyptic number.

20720878 is a deficient number, since it is larger than the sum of its proper divisors (10360442).

20720878 is a wasteful number, since it uses less digits than its factorization.

20720878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10360441.

The product of its (nonzero) digits is 12544, while the sum is 34.

The square root of 20720878 is about 4552.0191124379. The cubic root of 20720878 is about 274.6646181417.

The spelling of 20720878 in words is "twenty million, seven hundred twenty thousand, eight hundred seventy-eight".