21797719 has 8 divisors (see below), whose sum is σ = 22230288. Its totient is φ = 21369600.

The previous prime is 21797701. The next prime is 21797729. The reversal of 21797719 is 91779712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21797719 - 2⁷ = 21797591 is a prime.

It is a super-2 number, since 2×21797719² = 950281107205922, which contains 22 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 (21797729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9799 + ... + 11815.

It is an arithmetic number, because the mean of its divisors is an integer number (2778786).

Almost surely, 2^21797719 is an apocalyptic number.

21797719 is a deficient number, since it is larger than the sum of its proper divisors (432569).

21797719 is a wasteful number, since it uses less digits than its factorization.

21797719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2225.

The product of its digits is 55566, while the sum is 43.

The square root of 21797719 is about 4668.8027373193. The cubic root of 21797719 is about 279.3425006279.

The spelling of 21797719 in words is "twenty-one million, seven hundred ninety-seven thousand, seven hundred nineteen".