20784780 has 36 divisors (see below), whose sum is σ = 63047712. Its totient is φ = 5542560.

The previous prime is 20784767. The next prime is 20784791. The reversal of 20784780 is 8748702.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 57556 + ... + 57915.

Almost surely, 2^20784780 is an apocalyptic number.

20784780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20784780 is an abundant number, since it is smaller than the sum of its proper divisors (42262932).

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

20784780 is a wasteful number, since it uses less digits than its factorization.

20784780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115486 (or 115481 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 36.

The square root of 20784780 is about 4559.0327921611. The cubic root of 20784780 is about 274.9466783670.

The spelling of 20784780 in words is "twenty million, seven hundred eighty-four thousand, seven hundred eighty".