1861931 has 4 divisors (see below), whose sum is σ = 1880112. Its totient is φ = 1843752.

The previous prime is 1861927. The next prime is 1861961. The reversal of 1861931 is 1391681.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1861931 - 2² = 1861927 is a prime.

It is a super-2 number, since 2×1861931² = 6933574097522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1861894 and 1861903.

It is not an unprimeable number, because it can be changed into a prime (1861921) 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, 8936 + ... + 9141.

It is an arithmetic number, because the mean of its divisors is an integer number (470028).

2^1861931 is an apocalyptic number.

1861931 is a deficient number, since it is larger than the sum of its proper divisors (18181).

1861931 is a wasteful number, since it uses less digits than its factorization.

1861931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18180.

The product of its digits is 1296, while the sum is 29.

The square root of 1861931 is about 1364.5259250011. The cubic root of 1861931 is about 123.0234383695.

It can be divided in two parts, 1861 and 931, that multiplied together give a triangular number (1732591 = T₁₈₆₁).

The spelling of 1861931 in words is "one million, eight hundred sixty-one thousand, nine hundred thirty-one".