21196381 has 4 divisors (see below), whose sum is σ = 22312000. Its totient is φ = 20080764.

The previous prime is 21196349. The next prime is 21196397. The reversal of 21196381 is 18369112.

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 21196381 - 2⁵ = 21196349 is a prime.

It is a super-2 number, since 2×21196381² = 898573134994322, 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 (21196081) 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, 557781 + ... + 557818.

It is an arithmetic number, because the mean of its divisors is an integer number (5578000).

Almost surely, 2^21196381 is an apocalyptic number.

It is an amenable number.

21196381 is a deficient number, since it is larger than the sum of its proper divisors (1115619).

21196381 is a wasteful number, since it uses less digits than its factorization.

21196381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1115618.

The product of its digits is 2592, while the sum is 31.

The square root of 21196381 is about 4603.9527582285. The cubic root of 21196381 is about 276.7497511794.

The spelling of 21196381 in words is "twenty-one million, one hundred ninety-six thousand, three hundred eighty-one".