10021691 has 4 divisors (see below), whose sum is σ = 10032984. Its totient is φ = 10010400.

The previous prime is 10021663. The next prime is 10021699. The reversal of 10021691 is 19612001.

10021691 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10021691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10021699) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4190 + ... + 6131.

It is an arithmetic number, because the mean of its divisors is an integer number (2508246).

Almost surely, 2^10021691 is an apocalyptic number.

10021691 is a deficient number, since it is larger than the sum of its proper divisors (11293).

10021691 is an equidigital number, since it uses as much as digits as its factorization.

10021691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11292.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 10021691 is about 3165.7054506065. The cubic root of 10021691 is about 215.5991293193.

Adding to 10021691 its reverse (19612001), we get a palindrome (29633692).

The spelling of 10021691 in words is "ten million, twenty-one thousand, six hundred ninety-one".