2121381 has 12 divisors (see below), whose sum is σ = 3139500. Its totient is φ = 1379520.

The previous prime is 2121377. The next prime is 2121389. The reversal of 2121381 is 1831212.

It can be written as a sum of positive squares in 2 ways, for example, as 65025 + 2056356 = 255^2 + 1434^2 .

It is not a de Polignac number, because 2121381 - 2² = 2121377 is a prime.

It is a super-2 number, since 2×2121381² = 9000514694322, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121389) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2506 + ... + 3243.

It is an arithmetic number, because the mean of its divisors is an integer number (261625).

2^2121381 is an apocalyptic number.

It is an amenable number.

2121381 is a deficient number, since it is larger than the sum of its proper divisors (1018119).

2121381 is a wasteful number, since it uses less digits than its factorization.

2121381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5796 (or 5793 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 2121381 is about 1456.4961379969. The cubic root of 2121381 is about 128.4910539983.

Adding to 2121381 its reverse (1831212), we get a palindrome (3952593).

The spelling of 2121381 in words is "two million, one hundred twenty-one thousand, three hundred eighty-one".