1913621 has 4 divisors (see below), whose sum is σ = 1916544. Its totient is φ = 1910700.

The previous prime is 1913609. The next prime is 1913627. The reversal of 1913621 is 1263191.

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 1913621 - 2¹⁴ = 1897237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1913627) 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, 26 + ... + 1956.

It is an arithmetic number, because the mean of its divisors is an integer number (479136).

2^1913621 is an apocalyptic number.

It is an amenable number.

1913621 is a deficient number, since it is larger than the sum of its proper divisors (2923).

1913621 is an equidigital number, since it uses as much as digits as its factorization.

1913621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2922.

The product of its digits is 324, while the sum is 23.

The square root of 1913621 is about 1383.3369076259. The cubic root of 1913621 is about 124.1515014335.

It can be divided in two parts, 19136 and 21, that multiplied together give a triangular number (401856 = T₈₉₆).

The spelling of 1913621 in words is "one million, nine hundred thirteen thousand, six hundred twenty-one".