20434257 has 12 divisors (see below), whose sum is σ = 29555344. Its totient is φ = 13604760.

The previous prime is 20434247. The next prime is 20434259. The reversal of 20434257 is 75243402.

It is not a de Polignac number, because 20434257 - 2¹⁰ = 20433233 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20434257.

It is not an unprimeable number, because it can be changed into a prime (20434259) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12582 + ... + 14112.

Almost surely, 2^20434257 is an apocalyptic number.

It is an amenable number.

20434257 is a deficient number, since it is larger than the sum of its proper divisors (9121087).

20434257 is a wasteful number, since it uses less digits than its factorization.

20434257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3020 (or 3017 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 27.

The square root of 20434257 is about 4520.4266391570. The cubic root of 20434257 is about 273.3923031932.

Adding to 20434257 its reverse (75243402), we get a palindrome (95677659).

The spelling of 20434257 in words is "twenty million, four hundred thirty-four thousand, two hundred fifty-seven".