28691244 has 72 divisors (see below), whose sum is σ = 76597248. Its totient is φ = 9041760.

The previous prime is 28691219. The next prime is 28691261. The reversal of 28691244 is 44219682.

28691244 = 947² + 948² + ... + 977².

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 28691199 and 28691208.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 52179 + ... + 52725.

Almost surely, 2^28691244 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28691244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38298624).

28691244 is an abundant number, since it is smaller than the sum of its proper divisors (47906004).

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

28691244 is a wasteful number, since it uses less digits than its factorization.

28691244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 635 (or 630 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 28691244 is about 5356.4208199132. The cubic root of 28691244 is about 306.1374494647.

The spelling of 28691244 in words is "twenty-eight million, six hundred ninety-one thousand, two hundred forty-four".