1223742661 has 4 divisors (see below), whose sum is σ = 1230816492. Its totient is φ = 1216668832.

The previous prime is 1223742631. The next prime is 1223742677. The reversal of 1223742661 is 1662473221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1662473221 = 139 ⋅11960239.

It can be written as a sum of positive squares in 2 ways, for example, as 1173062500 + 50680161 = 34250^2 + 7119^2 .

It is a cyclic number.

It is not a de Polignac number, because 1223742661 - 2¹¹ = 1223740613 is a prime.

It is a super-2 number, since 2×1223742661² = 2995092200702721842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1223742631) 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, 3536656 + ... + 3537001.

It is an arithmetic number, because the mean of its divisors is an integer number (307704123).

Almost surely, 2^1223742661 is an apocalyptic number.

It is an amenable number.

1223742661 is a deficient number, since it is larger than the sum of its proper divisors (7073831).

1223742661 is an equidigital number, since it uses as much as digits as its factorization.

1223742661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7073830.

The product of its digits is 24192, while the sum is 34.

The square root of 1223742661 is about 34982.0334028770. The cubic root of 1223742661 is about 1069.6212771540.

The spelling of 1223742661 in words is "one billion, two hundred twenty-three million, seven hundred forty-two thousand, six hundred sixty-one".