1911496721 has 4 divisors (see below), whose sum is σ = 1952166912. Its totient is φ = 1870826532.

The previous prime is 1911496693. The next prime is 1911496739. The reversal of 1911496721 is 1276941191.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1276941191 = 337 ⋅3789143.

It is a cyclic number.

It is not a de Polignac number, because 1911496721 - 2²² = 1907302417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1911496771) 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, 20335025 + ... + 20335118.

It is an arithmetic number, because the mean of its divisors is an integer number (488041728).

Almost surely, 2^1911496721 is an apocalyptic number.

It is an amenable number.

1911496721 is a deficient number, since it is larger than the sum of its proper divisors (40670191).

1911496721 is an equidigital number, since it uses as much as digits as its factorization.

1911496721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40670190.

The product of its digits is 27216, while the sum is 41.

The square root of 1911496721 is about 43720.6669779865. Note that the first 3 decimals coincide. The cubic root of 1911496721 is about 1241.0554491513.

The spelling of 1911496721 in words is "one billion, nine hundred eleven million, four hundred ninety-six thousand, seven hundred twenty-one".