20780138 has 16 divisors (see below), whose sum is σ = 32140800. Its totient is φ = 10071600.

The previous prime is 20780119. The next prime is 20780141. The reversal of 20780138 is 83108702.

It is a self number, because there is not a number n which added to its sum of digits gives 20780138.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7463 + ... + 9861.

It is an arithmetic number, because the mean of its divisors is an integer number (2008800).

Almost surely, 2^20780138 is an apocalyptic number.

20780138 is a deficient number, since it is larger than the sum of its proper divisors (11360662).

20780138 is a wasteful number, since it uses less digits than its factorization.

20780138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2533.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 20780138 is about 4558.5236645212. The cubic root of 20780138 is about 274.9262083002.

The spelling of 20780138 in words is "twenty million, seven hundred eighty thousand, one hundred thirty-eight".