20542251 has 8 divisors (see below), whose sum is σ = 27720000. Its totient is φ = 13529672.

The previous prime is 20542213. The next prime is 20542253. The reversal of 20542251 is 15224502.

20542251 = 266² + 267² + ... + 431².

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20542251 - 2⁹ = 20541739 is a prime.

It is a super-2 number, since 2×20542251² = 843968152294002, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20542253) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41001 + ... + 41498.

It is an arithmetic number, because the mean of its divisors is an integer number (3465000).

Almost surely, 2^20542251 is an apocalyptic number.

20542251 is a deficient number, since it is larger than the sum of its proper divisors (7177749).

20542251 is an equidigital number, since it uses as much as digits as its factorization.

20542251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82585.

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 20542251 is about 4532.3560098474. The cubic root of 20542251 is about 273.8730786600.

Adding to 20542251 its reverse (15224502), we get a palindrome (35766753).

The spelling of 20542251 in words is "twenty million, five hundred forty-two thousand, two hundred fifty-one".