1021612721 has 4 divisors (see below), whose sum is σ = 1033921392. Its totient is φ = 1009304052.

The previous prime is 1021612687. The next prime is 1021612723. The reversal of 1021612721 is 1272161201.

1021612721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1272161201 = 3833 ⋅331897.

It is a cyclic number.

It is not a de Polignac number, because 1021612721 - 2²² = 1017418417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1021612723) 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, 6154211 + ... + 6154376.

It is an arithmetic number, because the mean of its divisors is an integer number (258480348).

Almost surely, 2^1021612721 is an apocalyptic number.

It is an amenable number.

1021612721 is a deficient number, since it is larger than the sum of its proper divisors (12308671).

1021612721 is an equidigital number, since it uses as much as digits as its factorization.

1021612721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12308670.

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 1021612721 is about 31962.6769999010. The cubic root of 1021612721 is about 1007.1529535952.

Adding to 1021612721 its reverse (1272161201), we get a palindrome (2293773922).

The spelling of 1021612721 in words is "one billion, twenty-one million, six hundred twelve thousand, seven hundred twenty-one".