1906681 has 4 divisors (see below), whose sum is σ = 2179072. Its totient is φ = 1634292.

The previous prime is 1906673. The next prime is 1906691. The reversal of 1906681 is 1866091.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1906681 - 2³ = 1906673 is a prime.

It is a super-2 number, since 2×1906681² = 7270864871522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1906621) 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, 136185 + ... + 136198.

It is an arithmetic number, because the mean of its divisors is an integer number (544768).

2^1906681 is an apocalyptic number.

It is an amenable number.

1906681 is a deficient number, since it is larger than the sum of its proper divisors (272391).

1906681 is an equidigital number, since it uses as much as digits as its factorization.

1906681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272390.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 1906681 is about 1380.8262019530. The cubic root of 1906681 is about 124.0012356797.

The spelling of 1906681 in words is "one million, nine hundred six thousand, six hundred eighty-one".