21775013 has 4 divisors (see below), whose sum is σ = 23450028. Its totient is φ = 20100000.

The previous prime is 21774983. The next prime is 21775031. The reversal of 21775013 is 31057712.

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 1181569 + 20593444 = 1087^2 + 4538^2 .

It is a cyclic number.

It is not a de Polignac number, because 21775013 - 2⁸ = 21774757 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21775063) 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, 837488 + ... + 837513.

It is an arithmetic number, because the mean of its divisors is an integer number (5862507).

Almost surely, 2^21775013 is an apocalyptic number.

It is an amenable number.

21775013 is a deficient number, since it is larger than the sum of its proper divisors (1675015).

21775013 is a wasteful number, since it uses less digits than its factorization.

21775013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1675014.

The product of its (nonzero) digits is 1470, while the sum is 26.

The square root of 21775013 is about 4666.3704310738. The cubic root of 21775013 is about 279.2454728236.

The spelling of 21775013 in words is "twenty-one million, seven hundred seventy-five thousand, thirteen".