21796381 has 8 divisors (see below), whose sum is σ = 22155840. Its totient is φ = 21439392.

The previous prime is 21796351. The next prime is 21796393. The reversal of 21796381 is 18369712.

21796381 = 163² + 164² + ... + 411².

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 21796381 - 2⁷ = 21796253 is a prime.

It is a super-2 number, since 2×21796381² = 950164449394322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21796381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21796321) 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, 25560 + ... + 26398.

It is an arithmetic number, because the mean of its divisors is an integer number (2769480).

Almost surely, 2^21796381 is an apocalyptic number.

It is an amenable number.

21796381 is a deficient number, since it is larger than the sum of its proper divisors (359459).

21796381 is an equidigital number, since it uses as much as digits as its factorization.

21796381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1235.

The product of its digits is 18144, while the sum is 37.

The square root of 21796381 is about 4668.6594435662. The cubic root of 21796381 is about 279.3367849241.

The spelling of 21796381 in words is "twenty-one million, seven hundred ninety-six thousand, three hundred eighty-one".