21219667 has 4 divisors (see below), whose sum is σ = 24251056. Its totient is φ = 18188280.

The previous prime is 21219641. The next prime is 21219703. The reversal of 21219667 is 76691212.

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 21219667 - 2²³ = 12831059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21219767) 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, 1515684 + ... + 1515697.

It is an arithmetic number, because the mean of its divisors is an integer number (6062764).

Almost surely, 2^21219667 is an apocalyptic number.

21219667 is a deficient number, since it is larger than the sum of its proper divisors (3031389).

21219667 is an equidigital number, since it uses as much as digits as its factorization.

21219667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3031388.

The product of its digits is 9072, while the sum is 34.

The square root of 21219667 is about 4606.4809779266. The cubic root of 21219667 is about 276.8510583513.

The spelling of 21219667 in words is "twenty-one million, two hundred nineteen thousand, six hundred sixty-seven".