21012442001 has 2 divisors, whose sum is σ = 21012442002. Its totient is φ = 21012442000.

The previous prime is 21012441997. The next prime is 21012442021. The reversal of 21012442001 is 10024421012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20541768976 + 470673025 = 143324^2 + 21695^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012442001 - 2² = 21012441997 is a prime.

It is not a weakly prime, because it can be changed into another prime (21012442021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506221000 + 10506221001.

It is an arithmetic number, because the mean of its divisors is an integer number (10506221001).

Almost surely, 2^21012442001 is an apocalyptic number.

It is an amenable number.

21012442001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012442001 is an equidigital number, since it uses as much as digits as its factorization.

21012442001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21012442001 its reverse (10024421012), we get a palindrome (31036863013).

The spelling of 21012442001 in words is "twenty-one billion, twelve million, four hundred forty-two thousand, one".