2153681 has 4 divisors (see below), whose sum is σ = 2199552. Its totient is φ = 2107812.

The previous prime is 2153647. The next prime is 2153693. The reversal of 2153681 is 1863512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2153681 - 2¹⁸ = 1891537 is a prime.

It is a super-2 number, since 2×2153681² = 9276683699522, which contains 22 as substring.

It is an Ulam number.

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 2153681.

It is not an unprimeable number, because it can be changed into a prime (2153621) 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, 22865 + ... + 22958.

It is an arithmetic number, because the mean of its divisors is an integer number (549888).

2^2153681 is an apocalyptic number.

It is an amenable number.

2153681 is a deficient number, since it is larger than the sum of its proper divisors (45871).

2153681 is an equidigital number, since it uses as much as digits as its factorization.

2153681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45870.

The product of its digits is 1440, while the sum is 26.

The square root of 2153681 is about 1467.5425036434. The cubic root of 2153681 is about 129.1399039014.

The spelling of 2153681 in words is "two million, one hundred fifty-three thousand, six hundred eighty-one".