1213652021 has 2 divisors, whose sum is σ = 1213652022. Its totient is φ = 1213652020.

The previous prime is 1213651993. The next prime is 1213652047. The reversal of 1213652021 is 1202563121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1209300625 + 4351396 = 34775^2 + 2086^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213652021 - 2¹⁴ = 1213635637 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 (1213652071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606826010 + 606826011.

It is an arithmetic number, because the mean of its divisors is an integer number (606826011).

Almost surely, 2^1213652021 is an apocalyptic number.

It is an amenable number.

1213652021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213652021 is an equidigital number, since it uses as much as digits as its factorization.

1213652021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 1213652021 is about 34837.5088231062. The cubic root of 1213652021 is about 1066.6732265981.

Subtracting from 1213652021 its reverse (1202563121), we obtain a square (11088900 = 3330²).

The spelling of 1213652021 in words is "one billion, two hundred thirteen million, six hundred fifty-two thousand, twenty-one".