21791145 has 8 divisors (see below), whose sum is σ = 34865856. Its totient is φ = 11621936.

The previous prime is 21791137. The next prime is 21791149. The reversal of 21791145 is 54119712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21791145 - 2³ = 21791137 is a prime.

It is a super-2 number, since 2×21791145² = 949708000822050, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21791149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 726357 + ... + 726386.

It is an arithmetic number, because the mean of its divisors is an integer number (4358232).

Almost surely, 2^21791145 is an apocalyptic number.

It is an amenable number.

21791145 is a deficient number, since it is larger than the sum of its proper divisors (13074711).

21791145 is a wasteful number, since it uses less digits than its factorization.

21791145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1452751.

The product of its digits is 2520, while the sum is 30.

The square root of 21791145 is about 4668.0986493432. The cubic root of 21791145 is about 279.3144153920.

The spelling of 21791145 in words is "twenty-one million, seven hundred ninety-one thousand, one hundred forty-five".