21010863 has 8 divisors (see below), whose sum is σ = 28187008. Its totient is φ = 13920984.

The previous prime is 21010859. The next prime is 21010883. The reversal of 21010863 is 36801012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21010863 - 2² = 21010859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010883) 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, 20995 + ... + 21972.

It is an arithmetic number, because the mean of its divisors is an integer number (3523376).

Almost surely, 2^21010863 is an apocalyptic number.

21010863 is a deficient number, since it is larger than the sum of its proper divisors (7176145).

21010863 is a wasteful number, since it uses less digits than its factorization.

21010863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43133.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21010863 is about 4583.7607921880. The cubic root of 21010863 is about 275.9399811732.

Adding to 21010863 its reverse (36801012), we get a palindrome (57811875).

The spelling of 21010863 in words is "twenty-one million, ten thousand, eight hundred sixty-three".