20971530 has 48 divisors (see below), whose sum is σ = 55804320. Its totient is φ = 5461344.

The previous prime is 20971529. The next prime is 20971537. The reversal of 20971530 is 3517902.

20971530 = 2046² + 2047² + ... + 2050².

It is a Curzon number.

It is a zygodrome in base 4.

It is a junction number, because it is equal to n+sod(n) for n = 20971494 and 20971503.

It is not an unprimeable number, because it can be changed into a prime (20971537) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1161 + ... + 6579.

It is an arithmetic number, because the mean of its divisors is an integer number (1162590).

Almost surely, 2^20971530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20971530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27902160).

20971530 is an abundant number, since it is smaller than the sum of its proper divisors (34832790).

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

20971530 is a wasteful number, since it uses less digits than its factorization.

20971530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5475 (or 5472 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 27.

The square root of 20971530 is about 4579.4683097495. The cubic root of 20971530 is about 275.7676841562.

The spelling of 20971530 in words is "twenty million, nine hundred seventy-one thousand, five hundred thirty".