21955013 has 4 divisors (see below), whose sum is σ = 23110560. Its totient is φ = 20799468.

The previous prime is 21954991. The next prime is 21955033. The reversal of 21955013 is 31055912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21955013 - 2¹⁰ = 21953989 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 (21955033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 577745 + ... + 577782.

It is an arithmetic number, because the mean of its divisors is an integer number (5777640).

Almost surely, 2^21955013 is an apocalyptic number.

It is an amenable number.

21955013 is a deficient number, since it is larger than the sum of its proper divisors (1155547).

21955013 is a wasteful number, since it uses less digits than its factorization.

21955013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1155546.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 21955013 is about 4685.6176753978. The cubic root of 21955013 is about 280.0128097881.

The spelling of 21955013 in words is "twenty-one million, nine hundred fifty-five thousand, thirteen".