22787991 has 12 divisors (see below), whose sum is σ = 33176832. Its totient is φ = 15071616.

The previous prime is 22787977. The next prime is 22787993. The reversal of 22787991 is 19978722.

It is not a de Polignac number, because 22787991 - 2¹¹ = 22785943 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22787993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8826 + ... + 11111.

It is an arithmetic number, because the mean of its divisors is an integer number (2764736).

Almost surely, 2^22787991 is an apocalyptic number.

22787991 is a deficient number, since it is larger than the sum of its proper divisors (10388841).

22787991 is a wasteful number, since it uses less digits than its factorization.

22787991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20070 (or 20067 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 22787991 is about 4773.6768847504. The cubic root of 22787991 is about 283.5101943835.

The spelling of 22787991 in words is "twenty-two million, seven hundred eighty-seven thousand, nine hundred ninety-one".