21510052001 has 2 divisors, whose sum is σ = 21510052002. Its totient is φ = 21510052000.

The previous prime is 21510051989. The next prime is 21510052049. The reversal of 21510052001 is 10025001512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19955800225 + 1554251776 = 141265^2 + 39424^2 .

It is a cyclic number.

It is not a de Polignac number, because 21510052001 - 2¹⁰ = 21510050977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21510051001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755026000 + 10755026001.

It is an arithmetic number, because the mean of its divisors is an integer number (10755026001).

Almost surely, 2^21510052001 is an apocalyptic number.

It is an amenable number.

21510052001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510052001 is an equidigital number, since it uses as much as digits as its factorization.

21510052001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 100, while the sum is 17.

Adding to 21510052001 its reverse (10025001512), we get a palindrome (31535053513).

The spelling of 21510052001 in words is "twenty-one billion, five hundred ten million, fifty-two thousand, one".