20101000 has 32 divisors (see below), whose sum is σ = 47038680. Its totient is φ = 8040000.

The previous prime is 20100991. The next prime is 20101001. The reversal of 20101000 is 10102.

It can be written as a sum of positive squares in 4 ways, for example, as 4435236 + 15665764 = 2106^2 + 3958^2 .

It is a Harshad number since it is a multiple of its sum of digits (4).

It is not an unprimeable number, because it can be changed into a prime (20101001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9051 + ... + 11050.

Almost surely, 2^20101000 is an apocalyptic number.

20101000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20101000 is an abundant number, since it is smaller than the sum of its proper divisors (26937680).

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

20101000 is a wasteful number, since it uses less digits than its factorization.

20101000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20122 (or 20108 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 4.

The square root of 20101000 is about 4483.4138778391. The cubic root of 20101000 is about 271.8979216152.

Adding to 20101000 its reverse (10102), we get a palindrome (20111102).

The spelling of 20101000 in words is "twenty million, one hundred one thousand".