7538191661 has 32 divisors (see below), whose sum is σ = 10221555456. Its totient is φ = 5368320000.

The previous prime is 7538191637. The next prime is 7538191673. The reversal of 7538191661 is 1661918357.

7538191661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 7538191661 - 2¹⁴ = 7538175277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7538191261) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 63821 + ... + 138381.

It is an arithmetic number, because the mean of its divisors is an integer number (319423608).

Almost surely, 2^7538191661 is an apocalyptic number.

It is an amenable number.

7538191661 is a deficient number, since it is larger than the sum of its proper divisors (2683363795).

7538191661 is a wasteful number, since it uses less digits than its factorization.

7538191661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74693.

The product of its digits is 272160, while the sum is 47.

The square root of 7538191661 is about 86822.7600402107. The cubic root of 7538191661 is about 1960.7507589181.

The spelling of 7538191661 in words is "seven billion, five hundred thirty-eight million, one hundred ninety-one thousand, six hundred sixty-one".