212515621 has 2 divisors, whose sum is σ = 212515622. Its totient is φ = 212515620.

The previous prime is 212515619. The next prime is 212515673. The reversal of 212515621 is 126515212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133056225 + 79459396 = 11535^2 + 8914^2 .

It is a cyclic number.

It is not a de Polignac number, because 212515621 - 2¹ = 212515619 is a prime.

Together with 212515619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212515601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106257810 + 106257811.

It is an arithmetic number, because the mean of its divisors is an integer number (106257811).

Almost surely, 2^212515621 is an apocalyptic number.

It is an amenable number.

212515621 is a deficient number, since it is larger than the sum of its proper divisors (1).

212515621 is an equidigital number, since it uses as much as digits as its factorization.

212515621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1200, while the sum is 25.

The square root of 212515621 is about 14577.9155231466. The cubic root of 212515621 is about 596.7562178806.

The spelling of 212515621 in words is "two hundred twelve million, five hundred fifteen thousand, six hundred twenty-one".