212515421 has 2 divisors, whose sum is σ = 212515422. Its totient is φ = 212515420.

The previous prime is 212515411. The next prime is 212515427. The reversal of 212515421 is 124515212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198415396 + 14100025 = 14086^2 + 3755^2 .

It is a cyclic number.

It is not a de Polignac number, because 212515421 - 2²⁶ = 145406557 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 (212515427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106257710 + 106257711.

It is an arithmetic number, because the mean of its divisors is an integer number (106257711).

Almost surely, 2^212515421 is an apocalyptic number.

It is an amenable number.

212515421 is a deficient number, since it is larger than the sum of its proper divisors (1).

212515421 is an equidigital number, since it uses as much as digits as its factorization.

212515421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 800, while the sum is 23.

The square root of 212515421 is about 14577.9086634538. The cubic root of 212515421 is about 596.7560306767.

The spelling of 212515421 in words is "two hundred twelve million, five hundred fifteen thousand, four hundred twenty-one".