21021021401 has 2 divisors, whose sum is σ = 21021021402. Its totient is φ = 21021021400.

The previous prime is 21021021389. The next prime is 21021021457. The reversal of 21021021401 is 10412012012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14086129225 + 6934892176 = 118685^2 + 83276^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021021401 - 2¹⁸ = 21020759257 is a prime.

It is not a weakly prime, because it can be changed into another prime (21021020401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510510700 + 10510510701.

It is an arithmetic number, because the mean of its divisors is an integer number (10510510701).

Almost surely, 2^21021021401 is an apocalyptic number.

It is an amenable number.

21021021401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021021401 is an equidigital number, since it uses as much as digits as its factorization.

21021021401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21021021401 its reverse (10412012012), we get a palindrome (31433033413).

The spelling of 21021021401 in words is "twenty-one billion, twenty-one million, twenty-one thousand, four hundred one".