1151287721 has 2 divisors, whose sum is σ = 1151287722. Its totient is φ = 1151287720.

The previous prime is 1151287699. The next prime is 1151287723. The reversal of 1151287721 is 1277821511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 851997721 + 299290000 = 29189^2 + 17300^2 .

It is a cyclic number.

It is not a de Polignac number, because 1151287721 - 2²² = 1147093417 is a prime.

Together with 1151287723, 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 (1151287723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 575643860 + 575643861.

It is an arithmetic number, because the mean of its divisors is an integer number (575643861).

Almost surely, 2^1151287721 is an apocalyptic number.

It is an amenable number.

1151287721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1151287721 is an equidigital number, since it uses as much as digits as its factorization.

1151287721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7840, while the sum is 35.

The square root of 1151287721 is about 33930.6310138789. The cubic root of 1151287721 is about 1048.0804600080.

The spelling of 1151287721 in words is "one billion, one hundred fifty-one million, two hundred eighty-seven thousand, seven hundred twenty-one".