11397821 has 4 divisors (see below), whose sum is σ = 11405472. Its totient is φ = 11390172.

The previous prime is 11397817. The next prime is 11397823. The reversal of 11397821 is 12879311.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 11397821 - 2² = 11397817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11397823) 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, 785 + ... + 4838.

It is an arithmetic number, because the mean of its divisors is an integer number (2851368).

Almost surely, 2^11397821 is an apocalyptic number.

It is an amenable number.

11397821 is a deficient number, since it is larger than the sum of its proper divisors (7651).

11397821 is an equidigital number, since it uses as much as digits as its factorization.

11397821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7650.

The product of its digits is 3024, while the sum is 32.

The square root of 11397821 is about 3376.0659057548. The cubic root of 11397821 is about 225.0473710958.

The spelling of 11397821 in words is "eleven million, three hundred ninety-seven thousand, eight hundred twenty-one".