21770129 has 2 divisors, whose sum is σ = 21770130. Its totient is φ = 21770128.

The previous prime is 21770093. The next prime is 21770141. The reversal of 21770129 is 92107712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15816529 + 5953600 = 3977^2 + 2440^2 .

It is a cyclic number.

It is not a de Polignac number, because 21770129 - 2¹² = 21766033 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21770179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10885064 + 10885065.

It is an arithmetic number, because the mean of its divisors is an integer number (10885065).

Almost surely, 2^21770129 is an apocalyptic number.

It is an amenable number.

21770129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21770129 is an equidigital number, since it uses as much as digits as its factorization.

21770129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1764, while the sum is 29.

The square root of 21770129 is about 4665.8470827921. The cubic root of 21770129 is about 279.2245935881.

The spelling of 21770129 in words is "twenty-one million, seven hundred seventy thousand, one hundred twenty-nine".