1631906 has 4 divisors (see below), whose sum is σ = 2447862. Its totient is φ = 815952.

The previous prime is 1631899. The next prime is 1631911. The reversal of 1631906 is 6091361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6091361 = 751 ⋅8111.

It can be written as a sum of positive squares in only one way, i.e., 1221025 + 410881 = 1105^2 + 641^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407975 + ... + 407978.

2^1631906 is an apocalyptic number.

1631906 is a deficient number, since it is larger than the sum of its proper divisors (815956).

1631906 is an equidigital number, since it uses as much as digits as its factorization.

1631906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 815955.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 1631906 is about 1277.4607626068. The cubic root of 1631906 is about 117.7330458533.

The spelling of 1631906 in words is "one million, six hundred thirty-one thousand, nine hundred six".