21001010 has 16 divisors (see below), whose sum is σ = 38606976. Its totient is φ = 8221488.

The previous prime is 21000983. The next prime is 21001021. The reversal of 21001010 is 1010012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (5).

It is a junction number, because it is equal to n+sod(n) for n = 21000985 and 21001003.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21872 + ... + 22811.

It is an arithmetic number, because the mean of its divisors is an integer number (2412936).

Almost surely, 2^21001010 is an apocalyptic number.

21001010 is a deficient number, since it is larger than the sum of its proper divisors (17605966).

21001010 is a wasteful number, since it uses less digits than its factorization.

21001010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44737.

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 21001010 is about 4582.6858936654. The cubic root of 21001010 is about 275.8968406044.

Adding to 21001010 its reverse (1010012), we get a palindrome (22011022).

The spelling of 21001010 in words is "twenty-one million, one thousand, ten".