1911000021221 has 4 divisors (see below), whose sum is σ = 1911003760512. Its totient is φ = 1910996281932.

The previous prime is 1911000021197. The next prime is 1911000021263. The reversal of 1911000021221 is 1221200001191.

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 1911000021221 - 2¹⁸ = 1910999759077 is a prime.

It is a super-2 number, since 2×1911000021221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1911000021193 and 1911000021202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1911000020221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 953375 + ... + 2175068.

It is an arithmetic number, because the mean of its divisors is an integer number (477750940128).

Almost surely, 2^{1911000021221} is an apocalyptic number.

It is an amenable number.

1911000021221 is a deficient number, since it is larger than the sum of its proper divisors (3739291).

1911000021221 is an equidigital number, since it uses as much as digits as its factorization.

1911000021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3739290.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 1911000021221 in words is "one trillion, nine hundred eleven billion, twenty-one thousand, two hundred twenty-one".