1010000021 has 2 divisors, whose sum is σ = 1010000022. Its totient is φ = 1010000020.

The previous prime is 1010000011. The next prime is 1010000029. The reversal of 1010000021 is 1200000101.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 992943121 + 17056900 = 31511^2 + 4130^2 .

It is an emirp because it is prime and its reverse (1200000101) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1010000021 - 2⁶ = 1009999957 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1010000029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 505000010 + 505000011.

It is an arithmetic number, because the mean of its divisors is an integer number (505000011).

Almost surely, 2^1010000021 is an apocalyptic number.

It is an amenable number.

1010000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1010000021 is an equidigital number, since it uses as much as digits as its factorization.

1010000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 1010000021 is about 31780.4974945327. The cubic root of 1010000021 is about 1003.3222904958.

Adding to 1010000021 its reverse (1200000101), we get a palindrome (2210000122).

The spelling of 1010000021 in words is "one billion, ten million, twenty-one", and thus it is an aban number and an uban number.