21021325009 has 2 divisors, whose sum is σ = 21021325010. Its totient is φ = 21021325008.

The previous prime is 21021324997. The next prime is 21021325069. The reversal of 21021325009 is 90052312012.

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., 15392124225 + 5629200784 = 124065^2 + 75028^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021325009 - 2²¹ = 21019227857 is a prime.

It is a super-2 number, since 2×21021325009² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21021325069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510662504 + 10510662505.

It is an arithmetic number, because the mean of its divisors is an integer number (10510662505).

Almost surely, 2^21021325009 is an apocalyptic number.

It is an amenable number.

21021325009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021325009 is an equidigital number, since it uses as much as digits as its factorization.

21021325009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The spelling of 21021325009 in words is "twenty-one billion, twenty-one million, three hundred twenty-five thousand, nine".