2135921 has 2 divisors, whose sum is σ = 2135922. Its totient is φ = 2135920.

The previous prime is 2135909. The next prime is 2135929. The reversal of 2135921 is 1295312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1345600 + 790321 = 1160^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 2135921 - 2⁶ = 2135857 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2135929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1067960 + 1067961.

It is an arithmetic number, because the mean of its divisors is an integer number (1067961).

2^2135921 is an apocalyptic number.

It is an amenable number.

2135921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2135921 is an equidigital number, since it uses as much as digits as its factorization.

2135921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 540, while the sum is 23.

The square root of 2135921 is about 1461.4790453510. The cubic root of 2135921 is about 128.7839461814.

The spelling of 2135921 in words is "two million, one hundred thirty-five thousand, nine hundred twenty-one".