21315301729 has 2 divisors, whose sum is σ = 21315301730. Its totient is φ = 21315301728.

The previous prime is 21315301703. The next prime is 21315301739. The reversal of 21315301729 is 92710351312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21243645504 + 71656225 = 145752^2 + 8465^2 .

It is a cyclic number.

It is not a de Polignac number, because 21315301729 - 2¹³ = 21315293537 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21315301694 and 21315301703.

It is not a weakly prime, because it can be changed into another prime (21315301739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10657650864 + 10657650865.

It is an arithmetic number, because the mean of its divisors is an integer number (10657650865).

Almost surely, 2^21315301729 is an apocalyptic number.

It is an amenable number.

21315301729 is a deficient number, since it is larger than the sum of its proper divisors (1).

21315301729 is an equidigital number, since it uses as much as digits as its factorization.

21315301729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11340, while the sum is 34.

The spelling of 21315301729 in words is "twenty-one billion, three hundred fifteen million, three hundred one thousand, seven hundred twenty-nine".