20731129 has 2 divisors, whose sum is σ = 20731130. Its totient is φ = 20731128.

The previous prime is 20731127. The next prime is 20731133. The reversal of 20731129 is 92113702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19404025 + 1327104 = 4405^2 + 1152^2 .

It is a cyclic number.

It is not a de Polignac number, because 20731129 - 2¹ = 20731127 is a prime.

It is a super-2 number, since 2×20731129² = 859559419229282, which contains 22 as substring.

Together with 20731127, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20731121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10365564 + 10365565.

It is an arithmetic number, because the mean of its divisors is an integer number (10365565).

Almost surely, 2^20731129 is an apocalyptic number.

It is an amenable number.

20731129 is a deficient number, since it is larger than the sum of its proper divisors (1).

20731129 is an equidigital number, since it uses as much as digits as its factorization.

20731129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 20731129 is about 4553.1449570599. The cubic root of 20731129 is about 274.7099045564.

The spelling of 20731129 in words is "twenty million, seven hundred thirty-one thousand, one hundred twenty-nine".