28949780 has 24 divisors (see below), whose sum is σ = 61031880. Its totient is φ = 11534720.

The previous prime is 28949779. The next prime is 28949857. The reversal of 28949780 is 8794982.

It can be written as a sum of positive squares in 4 ways, for example, as 26896 + 28922884 = 164^2 + 5378^2 .

It is a congruent number.

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, 2690 + ... + 8070.

It is an arithmetic number, because the mean of its divisors is an integer number (2542995).

Almost surely, 2^28949780 is an apocalyptic number.

28949780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is a pronic number, being equal to 5380×5381.

It is an amenable number.

28949780 is an abundant number, since it is smaller than the sum of its proper divisors (32082100).

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

28949780 is a wasteful number, since it uses less digits than its factorization.

28949780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5659 (or 5657 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 47.

The square root of 28949780 is about 5380.4999767680. The cubic root of 28949780 is about 307.0542332578.

The spelling of 28949780 in words is "twenty-eight million, nine hundred forty-nine thousand, seven hundred eighty".