1005400021 has 2 divisors, whose sum is σ = 1005400022. Its totient is φ = 1005400020.

The previous prime is 1005400013. The next prime is 1005400049. The reversal of 1005400021 is 1200045001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 610781796 + 394618225 = 24714^2 + 19865^2 .

It is a cyclic number.

It is not a de Polignac number, because 1005400021 - 2³ = 1005400013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1005399974 and 1005400010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1005400051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 502700010 + 502700011.

It is an arithmetic number, because the mean of its divisors is an integer number (502700011).

Almost surely, 2^1005400021 is an apocalyptic number.

It is an amenable number.

1005400021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1005400021 is an equidigital number, since it uses as much as digits as its factorization.

1005400021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 1005400021 is about 31708.0434748030. The cubic root of 1005400021 is about 1001.7967766601.

Adding to 1005400021 its reverse (1200045001), we get a palindrome (2205445022).

The spelling of 1005400021 in words is "one billion, five million, four hundred thousand, twenty-one".