20399229 has 32 divisors (see below), whose sum is σ = 31933440. Its totient is φ = 12844656.

The previous prime is 20399227. The next prime is 20399231. The reversal of 20399229 is 92299302.

It is an interprime number because it is at equal distance from previous prime (20399227) and next prime (20399231).

It is not a de Polignac number, because 20399229 - 2¹ = 20399227 is a prime.

It is a super-2 number, since 2×20399229² = 832257087588882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20399193 and 20399202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20399221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66294 + ... + 66600.

It is an arithmetic number, because the mean of its divisors is an integer number (997920).

Almost surely, 2^20399229 is an apocalyptic number.

It is an amenable number.

20399229 is a deficient number, since it is larger than the sum of its proper divisors (11534211).

20399229 is a wasteful number, since it uses less digits than its factorization.

20399229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446 (or 440 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 20399229 is about 4516.5505643134. The cubic root of 20399229 is about 273.2359992849.

The spelling of 20399229 in words is "twenty million, three hundred ninety-nine thousand, two hundred twenty-nine".