1901631 has 4 divisors (see below), whose sum is σ = 2535512. Its totient is φ = 1267752.

The previous prime is 1901597. The next prime is 1901639. The reversal of 1901631 is 1361091.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1901631 - 2⁶ = 1901567 is a prime.

It is a super-2 number, since 2×1901631² = 7232400920322, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1901598 and 1901607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1901639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 316936 + ... + 316941.

It is an arithmetic number, because the mean of its divisors is an integer number (633878).

2^1901631 is an apocalyptic number.

1901631 is a deficient number, since it is larger than the sum of its proper divisors (633881).

1901631 is an equidigital number, since it uses as much as digits as its factorization.

1901631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633880.

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 1901631 is about 1378.9963741794. The cubic root of 1901631 is about 123.8916630929.

The spelling of 1901631 in words is "one million, nine hundred one thousand, six hundred thirty-one".