21011121097 has 4 divisors (see below), whose sum is σ = 21014863360. Its totient is φ = 21007378836.

The previous prime is 21011121073. The next prime is 21011121127. The reversal of 21011121097 is 79012111012.

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 not a de Polignac number, because 21011121097 - 2¹⁹ = 21010596809 is a prime.

It is a super-3 number, since 3×21011121097³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21011125097) 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, 1862697 + ... + 1873942.

It is an arithmetic number, because the mean of its divisors is an integer number (5253715840).

Almost surely, 2^21011121097 is an apocalyptic number.

It is an amenable number.

21011121097 is a deficient number, since it is larger than the sum of its proper divisors (3742263).

21011121097 is an equidigital number, since it uses as much as digits as its factorization.

21011121097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3742262.

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

The spelling of 21011121097 in words is "twenty-one billion, eleven million, one hundred twenty-one thousand, ninety-seven".