21920063 has 4 divisors (see below), whose sum is σ = 23912808. Its totient is φ = 19927320.

The previous prime is 21920057. The next prime is 21920113. The reversal of 21920063 is 36002912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21920063 - 2⁴ = 21920047 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 (21920023) 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, 996356 + ... + 996377.

It is an arithmetic number, because the mean of its divisors is an integer number (5978202).

Almost surely, 2^21920063 is an apocalyptic number.

21920063 is a deficient number, since it is larger than the sum of its proper divisors (1992745).

21920063 is a wasteful number, since it uses less digits than its factorization.

21920063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1992744.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 21920063 is about 4681.8866923496. The cubic root of 21920063 is about 279.8641475321.

Adding to 21920063 its reverse (36002912), we get a palindrome (57922975).

The spelling of 21920063 in words is "twenty-one million, nine hundred twenty thousand, sixty-three".