21011012197 has 16 divisors (see below), whose sum is σ = 24806628352. Its totient is φ = 17414818560.

The previous prime is 21011012177. The next prime is 21011012273. The reversal of 21011012197 is 79121011012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21011012197 is a prime.

It is a super-3 number, since 3×21011012197³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011012177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 244123 + ... + 318775.

It is an arithmetic number, because the mean of its divisors is an integer number (1550414272).

Almost surely, 2^21011012197 is an apocalyptic number.

It is an amenable number.

21011012197 is a deficient number, since it is larger than the sum of its proper divisors (3795616155).

21011012197 is a wasteful number, since it uses less digits than its factorization.

21011012197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75988.

The product of its (nonzero) digits is 252, while the sum is 25.

The spelling of 21011012197 in words is "twenty-one billion, eleven million, twelve thousand, one hundred ninety-seven".