1121721751 has 2 divisors, whose sum is σ = 1121721752. Its totient is φ = 1121721750.

The previous prime is 1121721683. The next prime is 1121721823. The reversal of 1121721751 is 1571271211.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1121721751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1121721151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 560860875 + 560860876.

It is an arithmetic number, because the mean of its divisors is an integer number (560860876).

Almost surely, 2^1121721751 is an apocalyptic number.

1121721751 is a deficient number, since it is larger than the sum of its proper divisors (1).

1121721751 is an equidigital number, since it uses as much as digits as its factorization.

1121721751 is an evil number, because the sum of its binary digits is even.

The product of its digits is 980, while the sum is 28.

The square root of 1121721751 is about 33492.1147585518. The cubic root of 1121721751 is about 1039.0307015988.

Adding to 1121721751 its reverse (1571271211), we get a palindrome (2692992962).

The spelling of 1121721751 in words is "one billion, one hundred twenty-one million, seven hundred twenty-one thousand, seven hundred fifty-one".