2721212121 has 8 divisors (see below), whose sum is σ = 3631806144. Its totient is φ = 1812379760.

The previous prime is 2721212119. The next prime is 2721212159. The reversal of 2721212121 is 1212121272.

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

It is a cyclic number.

It is not a de Polignac number, because 2721212121 - 2¹ = 2721212119 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (2721212171) 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, 436806 + ... + 442991.

It is an arithmetic number, because the mean of its divisors is an integer number (453975768).

Almost surely, 2^2721212121 is an apocalyptic number.

It is an amenable number.

2721212121 is a deficient number, since it is larger than the sum of its proper divisors (910594023).

2721212121 is a wasteful number, since it uses less digits than its factorization.

2721212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880831.

The product of its digits is 224, while the sum is 21.

The square root of 2721212121 is about 52165.2386268864. The cubic root of 2721212121 is about 1396.1137324451.

Adding to 2721212121 its reverse (1212121272), we get a palindrome (3933333393).

The spelling of 2721212121 in words is "two billion, seven hundred twenty-one million, two hundred twelve thousand, one hundred twenty-one".