20515275 has 72 divisors (see below), whose sum is σ = 41705664. Its totient is φ = 9914400.

The previous prime is 20515249. The next prime is 20515283. The reversal of 20515275 is 57251502.

It is a happy number.

It is not a de Polignac number, because 20515275 - 2⁷ = 20515147 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 66672 + ... + 66978.

Almost surely, 2^20515275 is an apocalyptic number.

20515275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20515275 is an abundant number, since it is smaller than the sum of its proper divisors (21190389).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20515275 is a wasteful number, since it uses less digits than its factorization.

20515275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 3500, while the sum is 27.

The square root of 20515275 is about 4529.3790965208. The cubic root of 20515275 is about 273.7531431427.

Adding to 20515275 its reverse (57251502), we get a palindrome (77766777).

The spelling of 20515275 in words is "twenty million, five hundred fifteen thousand, two hundred seventy-five".