20515000 has 80 divisors (see below), whose sum is σ = 52576920. Its totient is φ = 7440000.

The previous prime is 20514979. The next prime is 20515007. The reversal of 20515000 is 51502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20515007) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 54814 + ... + 55186.

Almost surely, 2^20515000 is an apocalyptic number.

20515000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20515000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26288460).

20515000 is an abundant number, since it is smaller than the sum of its proper divisors (32061920).

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

20515000 is a wasteful number, since it uses less digits than its factorization.

20515000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410 (or 391 counting only the distinct ones).

The product of its (nonzero) digits is 50, while the sum is 13.

The square root of 20515000 is about 4529.3487390573. The cubic root of 20515000 is about 273.7519199493.

Adding to 20515000 its reverse (51502), we get a palindrome (20566502).

The spelling of 20515000 in words is "twenty million, five hundred fifteen thousand".