21226649 has 4 divisors (see below), whose sum is σ = 21720336. Its totient is φ = 20732964.

The previous prime is 21226633. The next prime is 21226663. The reversal of 21226649 is 94662212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21226649 - 2⁴ = 21226633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220649) 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, 246779 + ... + 246864.

It is an arithmetic number, because the mean of its divisors is an integer number (5430084).

Almost surely, 2^21226649 is an apocalyptic number.

It is an amenable number.

21226649 is a deficient number, since it is larger than the sum of its proper divisors (493687).

21226649 is an equidigital number, since it uses as much as digits as its factorization.

21226649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493686.

The product of its digits is 10368, while the sum is 32.

The square root of 21226649 is about 4607.2387609066. The cubic root of 21226649 is about 276.8814195272.

The spelling of 21226649 in words is "twenty-one million, two hundred twenty-six thousand, six hundred forty-nine".