21021030685 has 8 divisors (see below), whose sum is σ = 25228339200. Its totient is φ = 16814756304.

The previous prime is 21021030659. The next prime is 21021030691. The reversal of 21021030685 is 58603012012.

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

It is a cyclic number.

It is not a de Polignac number, because 21021030685 - 2²⁷ = 20886812957 is a prime.

It is a congruent number.

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, 213085 + ... + 295714.

It is an arithmetic number, because the mean of its divisors is an integer number (3153542400).

Almost surely, 2^21021030685 is an apocalyptic number.

It is an amenable number.

21021030685 is a deficient number, since it is larger than the sum of its proper divisors (4207308515).

21021030685 is an equidigital number, since it uses as much as digits as its factorization.

21021030685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517067.

The product of its (nonzero) digits is 2880, while the sum is 28.

Adding to 21021030685 its reverse (58603012012), we get a palindrome (79624042697).

The spelling of 21021030685 in words is "twenty-one billion, twenty-one million, thirty thousand, six hundred eighty-five".