1242151021 has 4 divisors (see below), whose sum is σ = 1242222592. Its totient is φ = 1242079452.

The previous prime is 1242150977. The next prime is 1242151061. The reversal of 1242151021 is 1201512421.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1242151021 - 2²⁷ = 1107933293 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1242151021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1242151061) 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, 8596 + ... + 50578.

It is an arithmetic number, because the mean of its divisors is an integer number (310555648).

Almost surely, 2^1242151021 is an apocalyptic number.

It is an amenable number.

1242151021 is a deficient number, since it is larger than the sum of its proper divisors (71571).

1242151021 is an equidigital number, since it uses as much as digits as its factorization.

1242151021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71570.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 1242151021 is about 35244.1629351585. The cubic root of 1242151021 is about 1074.9579276125.

Adding to 1242151021 its reverse (1201512421), we get a palindrome (2443663442).

The spelling of 1242151021 in words is "one billion, two hundred forty-two million, one hundred fifty-one thousand, twenty-one".