2152421 has 4 divisors (see below), whose sum is σ = 2279052. Its totient is φ = 2025792.

The previous prime is 2152399. The next prime is 2152427. The reversal of 2152421 is 1242512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 829921 + 1322500 = 911^2 + 1150^2 .

It is a cyclic number.

It is not a de Polignac number, because 2152421 - 2⁶ = 2152357 is a prime.

It is a super-2 number, since 2×2152421² = 9265832322482, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 126613 = 2152421 / (2 + 1 + 5 + 2 + 4 + 2 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2152421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2152427) 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, 63290 + ... + 63323.

It is an arithmetic number, because the mean of its divisors is an integer number (569763).

2^2152421 is an apocalyptic number.

It is an amenable number.

2152421 is a deficient number, since it is larger than the sum of its proper divisors (126631).

2152421 is a wasteful number, since it uses less digits than its factorization.

2152421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126630.

The product of its digits is 160, while the sum is 17.

The square root of 2152421 is about 1467.1131517371. The cubic root of 2152421 is about 129.1147147762.

Adding to 2152421 its reverse (1242512), we get a palindrome (3394933).

Subtracting from 2152421 its reverse (1242512), we obtain a palindrome (909909).

The spelling of 2152421 in words is "two million, one hundred fifty-two thousand, four hundred twenty-one".