11981421 has 6 divisors (see below), whose sum is σ = 17306510. Its totient is φ = 7987608.

The previous prime is 11981399. The next prime is 11981423. The reversal of 11981421 is 12418911.

It can be written as a sum of positive squares in only one way, i.e., 8037225 + 3944196 = 2835^2 + 1986^2 .

It is not a de Polignac number, because 11981421 - 2⁶ = 11981357 is a prime.

It is a Duffinian number.

It is a zygodrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11981423) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 665626 + ... + 665643.

Almost surely, 2^11981421 is an apocalyptic number.

It is an amenable number.

11981421 is a deficient number, since it is larger than the sum of its proper divisors (5325089).

11981421 is a wasteful number, since it uses less digits than its factorization.

11981421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1331275 (or 1331272 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The square root of 11981421 is about 3461.4189287054. The cubic root of 11981421 is about 228.8246338927.

The spelling of 11981421 in words is "eleven million, nine hundred eighty-one thousand, four hundred twenty-one".