2721561 has 8 divisors (see below), whose sum is σ = 3641664. Its totient is φ = 1807920.

The previous prime is 2721557. The next prime is 2721577. The reversal of 2721561 is 1651272.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2721561 - 2² = 2721557 is a prime.

2721561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2722561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 526 + ... + 2391.

It is an arithmetic number, because the mean of its divisors is an integer number (455208).

2^2721561 is an apocalyptic number.

It is an amenable number.

2721561 is a deficient number, since it is larger than the sum of its proper divisors (920103).

2721561 is a wasteful number, since it uses less digits than its factorization.

2721561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3231.

The product of its digits is 840, while the sum is 24.

The square root of 2721561 is about 1649.7154300060. The cubic root of 2721561 is about 139.6173393842.

The spelling of 2721561 in words is "two million, seven hundred twenty-one thousand, five hundred sixty-one".