20409780 has 48 divisors (see below), whose sum is σ = 58996224. Its totient is φ = 5266560.

The previous prime is 20409773. The next prime is 20409793. The reversal of 20409780 is 8790402.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

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, 3627 + ... + 7346.

It is an arithmetic number, because the mean of its divisors is an integer number (1229088).

Almost surely, 2^20409780 is an apocalyptic number.

20409780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20409780 is an abundant number, since it is smaller than the sum of its proper divisors (38586444).

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

20409780 is a wasteful number, since it uses less digits than its factorization.

20409780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11016 (or 11014 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 20409780 is about 4517.7184507227. The cubic root of 20409780 is about 273.2830993678.

The spelling of 20409780 in words is "twenty million, four hundred nine thousand, seven hundred eighty".