23197781 has 4 divisors (see below), whose sum is σ = 23427564. Its totient is φ = 22968000.

The previous prime is 23197747. The next prime is 23197789. The reversal of 23197781 is 18779132.

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

It can be written as a sum of positive squares in 2 ways, for example, as 20557156 + 2640625 = 4534^2 + 1625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23197781 is a prime.

It is a super-2 number, since 2×23197781² = 1076274086647922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23197789) by changing a digit.

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, 114740 + ... + 114941.

It is an arithmetic number, because the mean of its divisors is an integer number (5856891).

Almost surely, 2^23197781 is an apocalyptic number.

It is an amenable number.

23197781 is a deficient number, since it is larger than the sum of its proper divisors (229783).

23197781 is a wasteful number, since it uses less digits than its factorization.

23197781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229782.

The product of its digits is 21168, while the sum is 38.

The square root of 23197781 is about 4816.4074786089. The cubic root of 23197781 is about 285.1995360646.

The spelling of 23197781 in words is "twenty-three million, one hundred ninety-seven thousand, seven hundred eighty-one".