21362791 has 4 divisors (see below), whose sum is σ = 22291632. Its totient is φ = 20433952.

The previous prime is 21362753. The next prime is 21362827. The reversal of 21362791 is 19726312.

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 21362791 - 2¹¹ = 21360743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21362711) 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, 464386 + ... + 464431.

It is an arithmetic number, because the mean of its divisors is an integer number (5572908).

Almost surely, 2^21362791 is an apocalyptic number.

21362791 is a deficient number, since it is larger than the sum of its proper divisors (928841).

21362791 is an equidigital number, since it uses as much as digits as its factorization.

21362791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928840.

The product of its digits is 4536, while the sum is 31.

The square root of 21362791 is about 4621.9899394092. The cubic root of 21362791 is about 277.4721060619.

The spelling of 21362791 in words is "twenty-one million, three hundred sixty-two thousand, seven hundred ninety-one".