1157521261 has 4 divisors (see below), whose sum is σ = 1246561372. Its totient is φ = 1068481152.

The previous prime is 1157521259. The next prime is 1157521319. The reversal of 1157521261 is 1621257511.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 703575625 + 453945636 = 26525^2 + 21306^2 .

It is a cyclic number.

It is not a de Polignac number, because 1157521261 - 2¹ = 1157521259 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1157521231) 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, 44520036 + ... + 44520061.

It is an arithmetic number, because the mean of its divisors is an integer number (311640343).

Almost surely, 2^1157521261 is an apocalyptic number.

It is an amenable number.

1157521261 is a deficient number, since it is larger than the sum of its proper divisors (89040111).

1157521261 is an equidigital number, since it uses as much as digits as its factorization.

1157521261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89040110.

The product of its digits is 4200, while the sum is 31.

The square root of 1157521261 is about 34022.3641300836. The cubic root of 1157521261 is about 1049.9686342860.

Adding to 1157521261 its reverse (1621257511), we get a palindrome (2778778772).

The spelling of 1157521261 in words is "one billion, one hundred fifty-seven million, five hundred twenty-one thousand, two hundred sixty-one".