20150820 has 36 divisors (see below), whose sum is σ = 61124700. Its totient is φ = 5373504.

The previous prime is 20150761. The next prime is 20150821. The reversal of 20150820 is 2805102.

It can be written as a sum of positive squares in 2 ways, for example, as 2359296 + 17791524 = 1536^2 + 4218^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 20150793 and 20150802.

It is not an unprimeable number, because it can be changed into a prime (20150821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 55795 + ... + 56154.

Almost surely, 2^20150820 is an apocalyptic number.

20150820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20150820 is an abundant number, since it is smaller than the sum of its proper divisors (40973880).

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

20150820 is a wasteful number, since it uses less digits than its factorization.

20150820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111964 (or 111959 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 20150820 is about 4488.9664734769. The cubic root of 20150820 is about 272.1223678069.

Adding to 20150820 its reverse (2805102), we get a palindrome (22955922).

The spelling of 20150820 in words is "twenty million, one hundred fifty thousand, eight hundred twenty".