28193947 has 4 divisors (see below), whose sum is σ = 28367080. Its totient is φ = 28020816.

The previous prime is 28193941. The next prime is 28193969. The reversal of 28193947 is 74939182.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28193947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28193941) 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, 86322 + ... + 86647.

It is an arithmetic number, because the mean of its divisors is an integer number (7091770).

Almost surely, 2^28193947 is an apocalyptic number.

28193947 is a deficient number, since it is larger than the sum of its proper divisors (173133).

28193947 is a wasteful number, since it uses less digits than its factorization.

28193947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173132.

The product of its digits is 108864, while the sum is 43.

The square root of 28193947 is about 5309.7972654330. The cubic root of 28193947 is about 304.3584004457.

The spelling of 28193947 in words is "twenty-eight million, one hundred ninety-three thousand, nine hundred forty-seven".