28661971 has 4 divisors (see below), whose sum is σ = 30866752. Its totient is φ = 26457192.

The previous prime is 28661959. The next prime is 28661981. The reversal of 28661971 is 17916682.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28661971 - 2⁹ = 28661459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28661981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1102371 + ... + 1102396.

It is an arithmetic number, because the mean of its divisors is an integer number (7716688).

Almost surely, 2^28661971 is an apocalyptic number.

28661971 is a deficient number, since it is larger than the sum of its proper divisors (2204781).

28661971 is a wasteful number, since it uses less digits than its factorization.

28661971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2204780.

The product of its digits is 36288, while the sum is 40.

The square root of 28661971 is about 5353.6876076215. The cubic root of 28661971 is about 306.0332990946.

The spelling of 28661971 in words is "twenty-eight million, six hundred sixty-one thousand, nine hundred seventy-one".