1243151521 has 2 divisors, whose sum is σ = 1243151522. Its totient is φ = 1243151520.

The previous prime is 1243151509. The next prime is 1243151527. The reversal of 1243151521 is 1251513421.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 637007121 + 606144400 = 25239^2 + 24620^2 .

It is a cyclic number.

It is not a de Polignac number, because 1243151521 - 2¹⁵ = 1243118753 is a prime.

It is a super-2 number, since 2×1243151521² = 3090851408329226882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1243151527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621575760 + 621575761.

It is an arithmetic number, because the mean of its divisors is an integer number (621575761).

Almost surely, 2^1243151521 is an apocalyptic number.

It is an amenable number.

1243151521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243151521 is an equidigital number, since it uses as much as digits as its factorization.

1243151521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1200, while the sum is 25.

The square root of 1243151521 is about 35258.3539179015. The cubic root of 1243151521 is about 1075.2464611757.

Adding to 1243151521 its reverse (1251513421), we get a palindrome (2494664942).

The spelling of 1243151521 in words is "one billion, two hundred forty-three million, one hundred fifty-one thousand, five hundred twenty-one".