11981621 has 4 divisors (see below), whose sum is σ = 12044544. Its totient is φ = 11918700.

The previous prime is 11981603. The next prime is 11981623. The reversal of 11981621 is 12618911.

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 11981621 - 2¹⁴ = 11965237 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 (11981623) 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, 31175 + ... + 31556.

It is an arithmetic number, because the mean of its divisors is an integer number (3011136).

Almost surely, 2^11981621 is an apocalyptic number.

It is an amenable number.

11981621 is a deficient number, since it is larger than the sum of its proper divisors (62923).

11981621 is an equidigital number, since it uses as much as digits as its factorization.

11981621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62922.

The product of its digits is 864, while the sum is 29.

The square root of 11981621 is about 3461.4478184713. The cubic root of 11981621 is about 228.8259071048.

The spelling of 11981621 in words is "eleven million, nine hundred eighty-one thousand, six hundred twenty-one".