20612187221 has 4 divisors (see below), whose sum is σ = 21697039200. Its totient is φ = 19527335244.

The previous prime is 20612187209. The next prime is 20612187241. The reversal of 20612187221 is 12278121602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20612187221 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 (20612187241) 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, 542425961 + ... + 542425998.

It is an arithmetic number, because the mean of its divisors is an integer number (5424259800).

Almost surely, 2^20612187221 is an apocalyptic number.

It is an amenable number.

20612187221 is a deficient number, since it is larger than the sum of its proper divisors (1084851979).

20612187221 is a wasteful number, since it uses less digits than its factorization.

20612187221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1084851978.

The product of its (nonzero) digits is 5376, while the sum is 32.

The spelling of 20612187221 in words is "twenty billion, six hundred twelve million, one hundred eighty-seven thousand, two hundred twenty-one".