20472251 has 2 divisors, whose sum is σ = 20472252. Its totient is φ = 20472250.

The previous prime is 20472247. The next prime is 20472259. The reversal of 20472251 is 15227402.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20472251 - 2² = 20472247 is a prime.

It is a super-2 number, since 2×20472251² = 838226122014002, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20472259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10236125 + 10236126.

It is an arithmetic number, because the mean of its divisors is an integer number (10236126).

Almost surely, 2^20472251 is an apocalyptic number.

20472251 is a deficient number, since it is larger than the sum of its proper divisors (1).

20472251 is an equidigital number, since it uses as much as digits as its factorization.

20472251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 20472251 is about 4524.6271669608. The cubic root of 20472251 is about 273.5616403350.

Adding to 20472251 its reverse (15227402), we get a palindrome (35699653).

The spelling of 20472251 in words is "twenty million, four hundred seventy-two thousand, two hundred fifty-one".