21797967 has 4 divisors (see below), whose sum is σ = 29063960. Its totient is φ = 14531976.

The previous prime is 21797957. The next prime is 21797983. The reversal of 21797967 is 76979712.

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

It is not a de Polignac number, because 21797967 - 2⁶ = 21797903 is a prime.

It is a super-4 number, since 4×21797967⁴ (a number of 30 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21797957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3632992 + ... + 3632997.

It is an arithmetic number, because the mean of its divisors is an integer number (7265990).

Almost surely, 2^21797967 is an apocalyptic number.

21797967 is a deficient number, since it is larger than the sum of its proper divisors (7265993).

21797967 is an equidigital number, since it uses as much as digits as its factorization.

21797967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7265992.

The product of its digits is 333396, while the sum is 48.

The square root of 21797967 is about 4668.8292965153. The cubic root of 21797967 is about 279.3435600152.

The spelling of 21797967 in words is "twenty-one million, seven hundred ninety-seven thousand, nine hundred sixty-seven".