1243526661 has 20 divisors (see below), whose sum is σ = 2000508972. Its totient is φ = 765246528.

The previous prime is 1243526639. The next prime is 1243526677. The reversal of 1243526661 is 1666253421.

It can be written as a sum of positive squares in 2 ways, for example, as 612562500 + 630964161 = 24750^2 + 25119^2 .

It is not a de Polignac number, because 1243526661 - 2⁵ = 1243526629 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1243526681) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 589416 + ... + 591521.

Almost surely, 2^1243526661 is an apocalyptic number.

It is an amenable number.

1243526661 is a deficient number, since it is larger than the sum of its proper divisors (756982311).

1243526661 is a wasteful number, since it uses less digits than its factorization.

1243526661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1180962 (or 1180953 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The square root of 1243526661 is about 35263.6733906154. The cubic root of 1243526661 is about 1075.3546076575.

The spelling of 1243526661 in words is "one billion, two hundred forty-three million, five hundred twenty-six thousand, six hundred sixty-one".