20151243 has 24 divisors (see below), whose sum is σ = 34714368. Its totient is φ = 11013552.

The previous prime is 20151233. The next prime is 20151251. The reversal of 20151243 is 34215102.

It is not a de Polignac number, because 20151243 - 2⁴ = 20151227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20151233) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5505 + ... + 8402.

It is an arithmetic number, because the mean of its divisors is an integer number (1446432).

Almost surely, 2^20151243 is an apocalyptic number.

20151243 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

20151243 is a deficient number, since it is larger than the sum of its proper divisors (14563125).

20151243 is a wasteful number, since it uses less digits than its factorization.

20151243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13943 (or 13940 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20151243 is about 4489.0135887520. The cubic root of 20151243 is about 272.1242718974.

Adding to 20151243 its reverse (34215102), we get a palindrome (54366345).

The spelling of 20151243 in words is "twenty million, one hundred fifty-one thousand, two hundred forty-three".