1243400401 has 4 divisors (see below), whose sum is σ = 1297461312. Its totient is φ = 1189339492.

The previous prime is 1243400371. The next prime is 1243400437. The reversal of 1243400401 is 1040043421.

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: 1040043421 = 3851 ⋅270071.

It is a cyclic number.

It is not a de Polignac number, because 1243400401 - 2⁷ = 1243400273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1243400461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27030421 + ... + 27030466.

It is an arithmetic number, because the mean of its divisors is an integer number (324365328).

Almost surely, 2^1243400401 is an apocalyptic number.

It is an amenable number.

1243400401 is a deficient number, since it is larger than the sum of its proper divisors (54060911).

1243400401 is an equidigital number, since it uses as much as digits as its factorization.

1243400401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54060910.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 1243400401 is about 35261.8831176102. The cubic root of 1243400401 is about 1075.3182114755.

Adding to 1243400401 its reverse (1040043421), we get a palindrome (2283443822).

The spelling of 1243400401 in words is "one billion, two hundred forty-three million, four hundred thousand, four hundred one".