21002331953 has 2 divisors, whose sum is σ = 21002331954. Its totient is φ = 21002331952.

The previous prime is 21002331899. The next prime is 21002331983. The reversal of 21002331953 is 35913320012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14633015089 + 6369316864 = 120967^2 + 79808^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002331953 is a prime.

It is not a weakly prime, because it can be changed into another prime (21002331983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501165976 + 10501165977.

It is an arithmetic number, because the mean of its divisors is an integer number (10501165977).

Almost surely, 2^21002331953 is an apocalyptic number.

It is an amenable number.

21002331953 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002331953 is an equidigital number, since it uses as much as digits as its factorization.

21002331953 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4860, while the sum is 29.

Adding to 21002331953 its reverse (35913320012), we get a palindrome (56915651965).

The spelling of 21002331953 in words is "twenty-one billion, two million, three hundred thirty-one thousand, nine hundred fifty-three".