20170321921 has 8 divisors (see below), whose sum is σ = 20194108704. Its totient is φ = 20146552800.

The previous prime is 20170321909. The next prime is 20170321933. The reversal of 20170321921 is 12912307102.

It is an interprime number because it is at equal distance from previous prime (20170321909) and next prime (20170321933).

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 20170321921 - 2²³ = 20161933313 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20170321921.

It is not an unprimeable number, because it can be changed into a prime (20170321021) 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, 4334446 + ... + 4339096.

It is an arithmetic number, because the mean of its divisors is an integer number (2524263588).

Almost surely, 2^20170321921 is an apocalyptic number.

It is an amenable number.

20170321921 is a deficient number, since it is larger than the sum of its proper divisors (23786783).

20170321921 is a wasteful number, since it uses less digits than its factorization.

20170321921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8831.

The product of its (nonzero) digits is 1512, while the sum is 28.

The spelling of 20170321921 in words is "twenty billion, one hundred seventy million, three hundred twenty-one thousand, nine hundred twenty-one".