1961391 has 4 divisors (see below), whose sum is σ = 2615192. Its totient is φ = 1307592.

The previous prime is 1961381. The next prime is 1961411. The reversal of 1961391 is 1931691.

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

It is not a de Polignac number, because 1961391 - 2⁶ = 1961327 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1961321) 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, 326896 + ... + 326901.

It is an arithmetic number, because the mean of its divisors is an integer number (653798).

2^1961391 is an apocalyptic number.

1961391 is a deficient number, since it is larger than the sum of its proper divisors (653801).

1961391 is an equidigital number, since it uses as much as digits as its factorization.

1961391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 653800.

The product of its digits is 1458, while the sum is 30.

The square root of 1961391 is about 1400.4966976041. The cubic root of 1961391 is about 125.1760931465.

The spelling of 1961391 in words is "one million, nine hundred sixty-one thousand, three hundred ninety-one".