1921957 has 4 divisors (see below), whose sum is σ = 1968876. Its totient is φ = 1875040.

The previous prime is 1921937. The next prime is 1921967. The reversal of 1921957 is 7591291.

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

It can be written as a sum of positive squares in 2 ways, for example, as 75076 + 1846881 = 274^2 + 1359^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1921957 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 (1921937) 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, 23398 + ... + 23479.

It is an arithmetic number, because the mean of its divisors is an integer number (492219).

2^1921957 is an apocalyptic number.

It is an amenable number.

1921957 is a deficient number, since it is larger than the sum of its proper divisors (46919).

1921957 is an equidigital number, since it uses as much as digits as its factorization.

1921957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46918.

The product of its digits is 5670, while the sum is 34.

The square root of 1921957 is about 1386.3466377497. The cubic root of 1921957 is about 124.3315140518.

The spelling of 1921957 in words is "one million, nine hundred twenty-one thousand, nine hundred fifty-seven".