611991252 has 18 divisors (see below), whose sum is σ = 1546977978. Its totient is φ = 203997072.

The previous prime is 611991241. The next prime is 611991253. The reversal of 611991252 is 252199116.

It can be written as a sum of positive squares in only one way, i.e., 439489296 + 172501956 = 20964^2 + 13134^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 16999757 = 611991252 / (6 + 1 + 1 + 9 + 9 + 1 + 2 + 5 + 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (611991253) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8499843 + ... + 8499914.

It is an arithmetic number, because the mean of its divisors is an integer number (85943221).

Almost surely, 2^611991252 is an apocalyptic number.

It is an amenable number.

611991252 is an abundant number, since it is smaller than the sum of its proper divisors (934986726).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

611991252 is a wasteful number, since it uses less digits than its factorization.

611991252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16999767 (or 16999762 counting only the distinct ones).

The product of its digits is 9720, while the sum is 36.

The square root of 611991252 is about 24738.4569446035. The cubic root of 611991252 is about 849.0144295350.

The spelling of 611991252 in words is "six hundred eleven million, nine hundred ninety-one thousand, two hundred fifty-two".