1243274021 has 4 divisors (see below), whose sum is σ = 1356298944. Its totient is φ = 1130249100.

The previous prime is 1243274009. The next prime is 1243274027. The reversal of 1243274021 is 1204723421.

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: 1204723421 = 11 ⋅109520311.

It is a cyclic number.

It is not a de Polignac number, because 1243274021 - 2⁶ = 1243273957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1243274027) 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, 56512445 + ... + 56512466.

It is an arithmetic number, because the mean of its divisors is an integer number (339074736).

Almost surely, 2^1243274021 is an apocalyptic number.

1243274021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1243274021 is a deficient number, since it is larger than the sum of its proper divisors (113024923).

1243274021 is a wasteful number, since it uses less digits than its factorization.

1243274021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113024922.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 1243274021 is about 35260.0910520662. The cubic root of 1243274021 is about 1075.2817782343.

Adding to 1243274021 its reverse (1204723421), we get a palindrome (2447997442).

The spelling of 1243274021 in words is "one billion, two hundred forty-three million, two hundred seventy-four thousand, twenty-one".