189906681 has 8 divisors (see below), whose sum is σ = 260052544. Its totient is φ = 123182640.

The previous prime is 189906679. The next prime is 189906683. The reversal of 189906681 is 186609981.

It is an interprime number because it is at equal distance from previous prime (189906679) and next prime (189906683).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 189906681 - 2¹ = 189906679 is a prime.

It is a super-2 number, since 2×189906681² = 72129094976871522, which contains 22 as substring.

189906681 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 189906681.

It is not an unprimeable number, because it can be changed into a prime (189906683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 855325 + ... + 855546.

It is an arithmetic number, because the mean of its divisors is an integer number (32506568).

Almost surely, 2^189906681 is an apocalyptic number.

It is an amenable number.

189906681 is a deficient number, since it is larger than the sum of its proper divisors (70145863).

189906681 is a wasteful number, since it uses less digits than its factorization.

189906681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1710911.

The product of its (nonzero) digits is 186624, while the sum is 48.

The square root of 189906681 is about 13780.6633004366. The cubic root of 189906681 is about 574.7955729503.

The spelling of 189906681 in words is "one hundred eighty-nine million, nine hundred six thousand, six hundred eighty-one".