2154721 has 4 divisors (see below), whose sum is σ = 2162944. Its totient is φ = 2146500.

The previous prime is 2154707. The next prime is 2154727. The reversal of 2154721 is 1274512.

It is a happy number.

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 2154721 - 2⁹ = 2154209 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2154692 and 2154701.

It is not an unprimeable number, because it can be changed into a prime (2154727) 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, 3705 + ... + 4246.

It is an arithmetic number, because the mean of its divisors is an integer number (540736).

2^2154721 is an apocalyptic number.

It is an amenable number.

2154721 is a deficient number, since it is larger than the sum of its proper divisors (8223).

2154721 is an equidigital number, since it uses as much as digits as its factorization.

2154721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8222.

The product of its digits is 560, while the sum is 22.

The square root of 2154721 is about 1467.8967947373. The cubic root of 2154721 is about 129.1606875253.

The spelling of 2154721 in words is "two million, one hundred fifty-four thousand, seven hundred twenty-one".