21623113 has 4 divisors (see below), whose sum is σ = 22150548. Its totient is φ = 21095680.

The previous prime is 21623101. The next prime is 21623131. The reversal of 21623113 is 31132612.

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 8928144 + 12694969 = 2988^2 + 3563^2 .

It is a cyclic number.

It is not a de Polignac number, because 21623113 - 2⁵ = 21623081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21623153) 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, 263656 + ... + 263737.

It is an arithmetic number, because the mean of its divisors is an integer number (5537637).

Almost surely, 2^21623113 is an apocalyptic number.

It is an amenable number.

21623113 is a deficient number, since it is larger than the sum of its proper divisors (527435).

21623113 is an equidigital number, since it uses as much as digits as its factorization.

21623113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527434.

The product of its digits is 216, while the sum is 19.

The square root of 21623113 is about 4650.0659135113. The cubic root of 21623113 is about 278.5946289059.

Adding to 21623113 its reverse (31132612), we get a palindrome (52755725).

It can be divided in two parts, 21623 and 113, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21623113 in words is "twenty-one million, six hundred twenty-three thousand, one hundred thirteen".