1242572561 has 4 divisors (see below), whose sum is σ = 1242700800. Its totient is φ = 1242444324.

The previous prime is 1242572557. The next prime is 1242572563. The reversal of 1242572561 is 1652752421.

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: 1652752421 = 251 ⋅6584671.

It is a cyclic number.

It is not a de Polignac number, because 1242572561 - 2² = 1242572557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1242572563) 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, 48281 + ... + 69398.

It is an arithmetic number, because the mean of its divisors is an integer number (310675200).

Almost surely, 2^1242572561 is an apocalyptic number.

It is an amenable number.

1242572561 is a deficient number, since it is larger than the sum of its proper divisors (128239).

1242572561 is a wasteful number, since it uses less digits than its factorization.

1242572561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128238.

The product of its digits is 33600, while the sum is 35.

The square root of 1242572561 is about 35250.1427089310. The cubic root of 1242572561 is about 1075.0795141473.

The spelling of 1242572561 in words is "one billion, two hundred forty-two million, five hundred seventy-two thousand, five hundred sixty-one".