20531000 has 96 divisors (see below), whose sum is σ = 56019600. Its totient is φ = 7022400.

The previous prime is 20530987. The next prime is 20531023. The reversal of 20531000 is 13502.

It is a super-2 number, since 2×20531000² = 843043922000000, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48791 + ... + 49209.

Almost surely, 2^20531000 is an apocalyptic number.

20531000 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 20531000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28009800).

20531000 is an abundant number, since it is smaller than the sum of its proper divisors (35488600).

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

20531000 is a wasteful number, since it uses less digits than its factorization.

20531000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454 (or 433 counting only the distinct ones).

The product of its (nonzero) digits is 30, while the sum is 11.

The square root of 20531000 is about 4531.1146531510. The cubic root of 20531000 is about 273.8230693932.

Adding to 20531000 its reverse (13502), we get a palindrome (20544502).

The spelling of 20531000 in words is "twenty million, five hundred thirty-one thousand".