730000000021 has 2 divisors, whose sum is σ = 730000000022. Its totient is φ = 730000000020.

The previous prime is 730000000019. The next prime is 730000000057. The reversal of 730000000021 is 120000000037.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 729169119396 + 830880625 = 853914^2 + 28825^2 .

It is a cyclic number.

It is not a de Polignac number, because 730000000021 - 2¹ = 730000000019 is a prime.

Together with 730000000019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 729999999929 and 730000000010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (730000004021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 365000000010 + 365000000011.

It is an arithmetic number, because the mean of its divisors is an integer number (365000000011).

Almost surely, 2^730000000021 is an apocalyptic number.

It is an amenable number.

730000000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

730000000021 is an equidigital number, since it uses as much as digits as its factorization.

730000000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42, while the sum is 13.

Adding to 730000000021 its reverse (120000000037), we get a palindrome (850000000058).

The spelling of 730000000021 in words is "seven hundred thirty billion, twenty-one", and thus it is an aban number.