137691666 has 72 divisors (see below), whose sum is σ = 350522640. Its totient is φ = 38946096.

The previous prime is 137691661. The next prime is 137691679. The reversal of 137691666 is 666196731.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (137691661) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 93645 + ... + 95103.

It is an arithmetic number, because the mean of its divisors is an integer number (4868370).

Almost surely, 2^137691666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 137691666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (175261320).

137691666 is an abundant number, since it is smaller than the sum of its proper divisors (212830974).

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

137691666 is a wasteful number, since it uses less digits than its factorization.

137691666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1588 (or 1578 counting only the distinct ones).

The product of its digits is 244944, while the sum is 45.

The square root of 137691666 is about 11734.2092192018. The cubic root of 137691666 is about 516.3797682013.

The spelling of 137691666 in words is "one hundred thirty-seven million, six hundred ninety-one thousand, six hundred sixty-six".