21016220197 has 32 divisors (see below), whose sum is σ = 25369344000. Its totient is φ = 17384572800.

The previous prime is 21016220189. The next prime is 21016220209. The reversal of 21016220197 is 79102261012.

It is not a de Polignac number, because 21016220197 - 2³ = 21016220189 is a prime.

It is a super-2 number, since 2×21016220197² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21016220497) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4133697 + ... + 4138777.

It is an arithmetic number, because the mean of its divisors is an integer number (792792000).

Almost surely, 2^21016220197 is an apocalyptic number.

It is an amenable number.

21016220197 is a deficient number, since it is larger than the sum of its proper divisors (4353123803).

21016220197 is an equidigital number, since it uses as much as digits as its factorization.

21016220197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5522 (or 5508 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 31.

The spelling of 21016220197 in words is "twenty-one billion, sixteen million, two hundred twenty thousand, one hundred ninety-seven".