20829181 has 2 divisors, whose sum is σ = 20829182. Its totient is φ = 20829180.

The previous prime is 20829169. The next prime is 20829209. The reversal of 20829181 is 18192802.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17347225 + 3481956 = 4165^2 + 1866^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20829181 is a prime.

It is a super-2 number, since 2×20829181² = 867709562261522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20829581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10414590 + 10414591.

It is an arithmetic number, because the mean of its divisors is an integer number (10414591).

Almost surely, 2^20829181 is an apocalyptic number.

It is an amenable number.

20829181 is a deficient number, since it is larger than the sum of its proper divisors (1).

20829181 is an equidigital number, since it uses as much as digits as its factorization.

20829181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 20829181 is about 4563.8997578825. The cubic root of 20829181 is about 275.1423219231.

The spelling of 20829181 in words is "twenty million, eight hundred twenty-nine thousand, one hundred eighty-one".