611891921 has 4 divisors (see below), whose sum is σ = 612545892. Its totient is φ = 611237952.

The previous prime is 611891899. The next prime is 611891933. The reversal of 611891921 is 129198116.

611891921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 366531025 + 245360896 = 19145^2 + 15664^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-611891921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (611891971) 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, 325580 + ... + 327453.

It is an arithmetic number, because the mean of its divisors is an integer number (153136473).

Almost surely, 2^611891921 is an apocalyptic number.

It is an amenable number.

611891921 is a deficient number, since it is larger than the sum of its proper divisors (653971).

611891921 is an equidigital number, since it uses as much as digits as its factorization.

611891921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 653970.

The product of its digits is 7776, while the sum is 38.

The square root of 611891921 is about 24736.4492399374. The cubic root of 611891921 is about 848.9684931401.

The spelling of 611891921 in words is "six hundred eleven million, eight hundred ninety-one thousand, nine hundred twenty-one".