212651581 has 2 divisors, whose sum is σ = 212651582. Its totient is φ = 212651580.

The previous prime is 212651567. The next prime is 212651587. The reversal of 212651581 is 185156212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 153884025 + 58767556 = 12405^2 + 7666^2 .

It is a cyclic number.

It is not a de Polignac number, because 212651581 - 2⁹ = 212651069 is a prime.

It is a super-2 number, since 2×212651581² = 90441389803599122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212651587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106325790 + 106325791.

It is an arithmetic number, because the mean of its divisors is an integer number (106325791).

Almost surely, 2^212651581 is an apocalyptic number.

It is an amenable number.

212651581 is a deficient number, since it is larger than the sum of its proper divisors (1).

212651581 is an equidigital number, since it uses as much as digits as its factorization.

212651581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4800, while the sum is 31.

The square root of 212651581 is about 14582.5779956769. The cubic root of 212651581 is about 596.8834519458.

The spelling of 212651581 in words is "two hundred twelve million, six hundred fifty-one thousand, five hundred eighty-one".