28220740 has 12 divisors (see below), whose sum is σ = 59263596. Its totient is φ = 11288288.

The previous prime is 28220737. The next prime is 28220761. The reversal of 28220740 is 4702282.

It can be written as a sum of positive squares in 2 ways, for example, as 18783556 + 9437184 = 4334^2 + 3072^2 .

It is a super-2 number, since 2×28220740² = 1592820332295200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 705499 + ... + 705538.

It is an arithmetic number, because the mean of its divisors is an integer number (4938633).

Almost surely, 2^28220740 is an apocalyptic number.

28220740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28220740 is an abundant number, since it is smaller than the sum of its proper divisors (31042856).

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

28220740 is a wasteful number, since it uses less digits than its factorization.

28220740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1411046 (or 1411044 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 25.

The square root of 28220740 is about 5312.3196439973. The cubic root of 28220740 is about 304.4547815688.

The spelling of 28220740 in words is "twenty-eight million, two hundred twenty thousand, seven hundred forty".