21863091 has 16 divisors (see below), whose sum is σ = 31677440. Its totient is φ = 13361760.

The previous prime is 21863081. The next prime is 21863119. The reversal of 21863091 is 19036812.

It is not a de Polignac number, because 21863091 - 2⁹ = 21862579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21863011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4420 + ... + 7953.

It is an arithmetic number, because the mean of its divisors is an integer number (1979840).

Almost surely, 2^21863091 is an apocalyptic number.

21863091 is a deficient number, since it is larger than the sum of its proper divisors (9814349).

21863091 is a wasteful number, since it uses less digits than its factorization.

21863091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12426.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21863091 is about 4675.7984344922. The cubic root of 21863091 is about 279.6214740538.

The spelling of 21863091 in words is "twenty-one million, eight hundred sixty-three thousand, ninety-one".