1258732661 has 4 divisors (see below), whose sum is σ = 1313460192. Its totient is φ = 1204005132.

The previous prime is 1258732639. The next prime is 1258732663. The reversal of 1258732661 is 1662378521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1662378521 = 23 ⋅72277327.

It is a cyclic number.

It is not a de Polignac number, because 1258732661 - 2¹⁰ = 1258731637 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 (1258732663) 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, 27363731 + ... + 27363776.

It is an arithmetic number, because the mean of its divisors is an integer number (328365048).

Almost surely, 2^1258732661 is an apocalyptic number.

It is an amenable number.

1258732661 is a deficient number, since it is larger than the sum of its proper divisors (54727531).

1258732661 is an equidigital number, since it uses as much as digits as its factorization.

1258732661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54727530.

The product of its digits is 120960, while the sum is 41.

The square root of 1258732661 is about 35478.6225916396. The cubic root of 1258732661 is about 1079.7200523265.

The spelling of 1258732661 in words is "one billion, two hundred fifty-eight million, seven hundred thirty-two thousand, six hundred sixty-one".