1420400021 has 2 divisors, whose sum is σ = 1420400022. Its totient is φ = 1420400020.

The previous prime is 1420400017. The next prime is 1420400027. The reversal of 1420400021 is 1200040241.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 713637796 + 706762225 = 26714^2 + 26585^2 .

It is an emirp because it is prime and its reverse (1200040241) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1420400021 - 2² = 1420400017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1420399969 and 1420400005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1420400027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 710200010 + 710200011.

It is an arithmetic number, because the mean of its divisors is an integer number (710200011).

Almost surely, 2^1420400021 is an apocalyptic number.

It is an amenable number.

1420400021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1420400021 is an equidigital number, since it uses as much as digits as its factorization.

1420400021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 1420400021 is about 37688.1947166483. The cubic root of 1420400021 is about 1124.0963992941.

Adding to 1420400021 its reverse (1200040241), we get a palindrome (2620440262).

The spelling of 1420400021 in words is "one billion, four hundred twenty million, four hundred thousand, twenty-one".