1242721356 has 24 divisors (see below), whose sum is σ = 2904524784. Its totient is φ = 413548800.

The previous prime is 1242721351. The next prime is 1242721367. The reversal of 1242721356 is 6531272421.

It is not an unprimeable number, because it can be changed into a prime (1242721351) 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, 78945 + ... + 93368.

It is an arithmetic number, because the mean of its divisors is an integer number (121021866).

Almost surely, 2^1242721356 is an apocalyptic number.

It is an amenable number.

1242721356 is an abundant number, since it is smaller than the sum of its proper divisors (1661803428).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1242721356 is a wasteful number, since it uses less digits than its factorization.

1242721356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172921 (or 172919 counting only the distinct ones).

The product of its digits is 20160, while the sum is 33.

The square root of 1242721356 is about 35252.2532045825. The cubic root of 1242721356 is about 1075.1224251414.

Adding to 1242721356 its reverse (6531272421), we get a palindrome (7773993777).

The spelling of 1242721356 in words is "one billion, two hundred forty-two million, seven hundred twenty-one thousand, three hundred fifty-six".