28972861 has 6 divisors (see below), whose sum is σ = 29244410. Its totient is φ = 28703808.

The previous prime is 28972859. The next prime is 28972871. The reversal of 28972861 is 16827982.

It can be written as a sum of positive squares in 3 ways, for example, as 7868025 + 21104836 = 2805^2 + 4594^2 .

It is not a de Polignac number, because 28972861 - 2¹ = 28972859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28972871) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11635 + ... + 13903.

Almost surely, 2^28972861 is an apocalyptic number.

It is an amenable number.

28972861 is a deficient number, since it is larger than the sum of its proper divisors (271549).

28972861 is an equidigital number, since it uses as much as digits as its factorization.

28972861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2495 (or 2382 counting only the distinct ones).

The product of its digits is 96768, while the sum is 43.

The square root of 28972861 is about 5382.6444244442. The cubic root of 28972861 is about 307.1358140289.

The spelling of 28972861 in words is "twenty-eight million, nine hundred seventy-two thousand, eight hundred sixty-one".