21221011097 has 18 divisors (see below), whose sum is σ = 25257894606. Its totient is φ = 17807824320.

The previous prime is 21221011079. The next prime is 21221011127. The reversal of 21221011097 is 79011012212.

It can be written as a sum of positive squares in 3 ways, for example, as 341917081 + 20879094016 = 18491^2 + 144496^2 .

It is not a de Polignac number, because 21221011097 - 2²⁰ = 21219962521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221011297) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 498428 + ... + 539325.

It is an arithmetic number, because the mean of its divisors is an integer number (1403216367).

Almost surely, 2^21221011097 is an apocalyptic number.

It is an amenable number.

21221011097 is a deficient number, since it is larger than the sum of its proper divisors (4036883509).

21221011097 is a wasteful number, since it uses less digits than its factorization.

21221011097 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1037801 (or 1037777 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 26.

The spelling of 21221011097 in words is "twenty-one billion, two hundred twenty-one million, eleven thousand, ninety-seven".