1242845821 has 8 divisors (see below), whose sum is σ = 1420614720. Its totient is φ = 1065131808.

The previous prime is 1242845801. The next prime is 1242845839. The reversal of 1242845821 is 1285482421.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1242845821 - 2⁷ = 1242845693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1242845801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 64710 + ... + 81688.

It is an arithmetic number, because the mean of its divisors is an integer number (177576840).

Almost surely, 2^1242845821 is an apocalyptic number.

It is an amenable number.

1242845821 is a deficient number, since it is larger than the sum of its proper divisors (177768899).

1242845821 is a wasteful number, since it uses less digits than its factorization.

1242845821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27443.

The product of its digits is 40960, while the sum is 37.

The square root of 1242845821 is about 35254.0185085332. The cubic root of 1242845821 is about 1075.1583169753.

The spelling of 1242845821 in words is "one billion, two hundred forty-two million, eight hundred forty-five thousand, eight hundred twenty-one".