33121381 has 2 divisors, whose sum is σ = 33121382. Its totient is φ = 33121380.

The previous prime is 33121367. The next prime is 33121391. The reversal of 33121381 is 18312133.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21622500 + 11498881 = 4650^2 + 3391^2 .

It is a cyclic number.

It is not a de Polignac number, because 33121381 - 2¹³ = 33113189 is a prime.

It is a super-2 number, since 2×33121381² = 2194051758694322, which contains 22 as substring.

It is equal to p_2038630 and since 33121381 and 2038630 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (33121301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16560690 + 16560691.

It is an arithmetic number, because the mean of its divisors is an integer number (16560691).

Almost surely, 2^33121381 is an apocalyptic number.

It is an amenable number.

33121381 is a deficient number, since it is larger than the sum of its proper divisors (1).

33121381 is an equidigital number, since it uses as much as digits as its factorization.

33121381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 22.

The square root of 33121381 is about 5755.1178093937. The cubic root of 33121381 is about 321.1462181985.

It can be divided in two parts, 331 and 21381, that added together give a palindrome (21712).

The spelling of 33121381 in words is "thirty-three million, one hundred twenty-one thousand, three hundred eighty-one".