210151681 has 2 divisors, whose sum is σ = 210151682. Its totient is φ = 210151680.

The previous prime is 210151651. The next prime is 210151699. The reversal of 210151681 is 186151012.

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., 210105025 + 46656 = 14495^2 + 216^2 .

It is a cyclic number.

It is not a de Polignac number, because 210151681 - 2⁹ = 210151169 is a prime.

It is a super-2 number, since 2×210151681² = 88327458054251522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (210151651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105075840 + 105075841.

It is an arithmetic number, because the mean of its divisors is an integer number (105075841).

Almost surely, 2^210151681 is an apocalyptic number.

It is an amenable number.

210151681 is a deficient number, since it is larger than the sum of its proper divisors (1).

210151681 is an equidigital number, since it uses as much as digits as its factorization.

210151681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 25.

The square root of 210151681 is about 14496.6092932106. The cubic root of 210151681 is about 594.5352687756.

It can be divided in two parts, 21015 and 1681, that multiplied together give a triangular number (35326215 = T₈₄₀₅).

The spelling of 210151681 in words is "two hundred ten million, one hundred fifty-one thousand, six hundred eighty-one".