20784138 has 32 divisors (see below), whose sum is σ = 43967040. Its totient is φ = 6531840.

The previous prime is 20784077. The next prime is 20784143. The reversal of 20784138 is 83148702.

It is a junction number, because it is equal to n+sod(n) for n = 20784099 and 20784108.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38148 + ... + 38688.

It is an arithmetic number, because the mean of its divisors is an integer number (1373970).

Almost surely, 2^20784138 is an apocalyptic number.

20784138 is an abundant number, since it is smaller than the sum of its proper divisors (23182902).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20784138 is a wasteful number, since it uses less digits than its factorization.

20784138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 902.

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 20784138 is about 4558.9623819461. The cubic root of 20784138 is about 274.9438474881.

It can be divided in two parts, 2078 and 4138, that added together give a triangular number (6216 = T₁₁₁).

The spelling of 20784138 in words is "twenty million, seven hundred eighty-four thousand, one hundred thirty-eight".