1234400021 has 2 divisors, whose sum is σ = 1234400022. Its totient is φ = 1234400020.

The previous prime is 1234400017. The next prime is 1234400047. The reversal of 1234400021 is 1200044321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1078399921 + 156000100 = 32839^2 + 12490^2 .

It is a cyclic number.

It is not a de Polignac number, because 1234400021 - 2² = 1234400017 is a prime.

It is a super-3 number, since 3×1234400021³ (a number of 28 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1234402021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 617200010 + 617200011.

It is an arithmetic number, because the mean of its divisors is an integer number (617200011).

Almost surely, 2^1234400021 is an apocalyptic number.

It is an amenable number.

1234400021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1234400021 is an equidigital number, since it uses as much as digits as its factorization.

1234400021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 1234400021 is about 35134.0293874756. The cubic root of 1234400021 is about 1072.7173547156.

Adding to 1234400021 its reverse (1200044321), we get a palindrome (2434444342).

The spelling of 1234400021 in words is "one billion, two hundred thirty-four million, four hundred thousand, twenty-one".