1242128451 has 4 divisors (see below), whose sum is σ = 1656171272. Its totient is φ = 828085632.

The previous prime is 1242128413. The next prime is 1242128467. The reversal of 1242128451 is 1548212421.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1242128451 - 2⁷ = 1242128323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1242128051) 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, 207021406 + ... + 207021411.

It is an arithmetic number, because the mean of its divisors is an integer number (414042818).

Almost surely, 2^1242128451 is an apocalyptic number.

1242128451 is a deficient number, since it is larger than the sum of its proper divisors (414042821).

1242128451 is an equidigital number, since it uses as much as digits as its factorization.

1242128451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414042820.

The product of its digits is 5120, while the sum is 30.

The square root of 1242128451 is about 35243.8427388388. The cubic root of 1242128451 is about 1074.9514168778.

The spelling of 1242128451 in words is "one billion, two hundred forty-two million, one hundred twenty-eight thousand, four hundred fifty-one".