20428780 has 24 divisors (see below), whose sum is σ = 43298640. Its totient is φ = 8095680.

The previous prime is 20428777. The next prime is 20428799. The reversal of 20428780 is 8782402.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2506 + ... + 6865.

It is an arithmetic number, because the mean of its divisors is an integer number (1804110).

Almost surely, 2^20428780 is an apocalyptic number.

20428780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20428780 is an abundant number, since it is smaller than the sum of its proper divisors (22869860).

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

20428780 is a wasteful number, since it uses less digits than its factorization.

20428780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9489 (or 9487 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 31.

The square root of 20428780 is about 4519.8207929076. The cubic root of 20428780 is about 273.3678752037.

The spelling of 20428780 in words is "twenty million, four hundred twenty-eight thousand, seven hundred eighty".