1051228721 has 2 divisors, whose sum is σ = 1051228722. Its totient is φ = 1051228720.

The previous prime is 1051228709. The next prime is 1051228723. The reversal of 1051228721 is 1278221501.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 564585121 + 486643600 = 23761^2 + 22060^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1051228721 is a prime.

It is a super-2 number, since 2×1051228721² = 2210163647710591682, which contains 22 as substring.

Together with 1051228723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1051228723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 525614360 + 525614361.

It is an arithmetic number, because the mean of its divisors is an integer number (525614361).

Almost surely, 2^1051228721 is an apocalyptic number.

It is an amenable number.

1051228721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1051228721 is an equidigital number, since it uses as much as digits as its factorization.

1051228721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2240, while the sum is 29.

The square root of 1051228721 is about 32422.6575252554. The cubic root of 1051228721 is about 1016.7926681540.

The spelling of 1051228721 in words is "one billion, fifty-one million, two hundred twenty-eight thousand, seven hundred twenty-one".