21930653 has 4 divisors (see below), whose sum is σ = 21987420. Its totient is φ = 21873888.

The previous prime is 21930647. The next prime is 21930673. The reversal of 21930653 is 35603912.

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 2199289 + 19731364 = 1483^2 + 4442^2 .

It is a cyclic number.

It is not a de Polignac number, because 21930653 - 2⁶ = 21930589 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 (21930673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27800 + ... + 28577.

It is an arithmetic number, because the mean of its divisors is an integer number (5496855).

Almost surely, 2^21930653 is an apocalyptic number.

It is an amenable number.

21930653 is a deficient number, since it is larger than the sum of its proper divisors (56767).

21930653 is an equidigital number, since it uses as much as digits as its factorization.

21930653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56766.

The product of its (nonzero) digits is 4860, while the sum is 29.

The square root of 21930653 is about 4683.0175101103. The cubic root of 21930653 is about 279.9092095098.

The spelling of 21930653 in words is "twenty-one million, nine hundred thirty thousand, six hundred fifty-three".