21223701 has 20 divisors (see below), whose sum is σ = 33571692. Its totient is φ = 13315968.

The previous prime is 21223693. The next prime is 21223711. The reversal of 21223701 is 10732212.

It can be written as a sum of positive squares in 2 ways, for example, as 17514225 + 3709476 = 4185^2 + 1926^2 .

It is not a de Polignac number, because 21223701 - 2³ = 21223693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21223711) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6330 + ... + 9083.

Almost surely, 2^21223701 is an apocalyptic number.

It is an amenable number.

21223701 is a deficient number, since it is larger than the sum of its proper divisors (12347991).

21223701 is a wasteful number, since it uses less digits than its factorization.

21223701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15442 (or 15433 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21223701 is about 4606.9188184729. The cubic root of 21223701 is about 276.8686009830.

Adding to 21223701 its reverse (10732212), we get a palindrome (31955913).

The spelling of 21223701 in words is "twenty-one million, two hundred twenty-three thousand, seven hundred one".