1971945 has 28 divisors (see below), whose sum is σ = 3554436. Its totient is φ = 1049760.

The previous prime is 1971911. The next prime is 1971967. The reversal of 1971945 is 5491791.

It can be written as a sum of positive squares in 2 ways, for example, as 746496 + 1225449 = 864^2 + 1107^2 .

It is not a de Polignac number, because 1971945 - 2⁹ = 1971433 is a prime.

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 3375 + ... + 3915.

2^1971945 is an apocalyptic number.

1971945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1971945 is a deficient number, since it is larger than the sum of its proper divisors (1582491).

1971945 is an frugal number, since it uses more digits than its factorization.

1971945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564 (or 549 counting only the distinct ones).

The product of its digits is 11340, while the sum is 36.

The square root of 1971945 is about 1404.2595913862. The cubic root of 1971945 is about 125.4002106175.

It can be divided in two parts, 1971 and 945, that added together give a square (2916 = 54²).

The spelling of 1971945 in words is "one million, nine hundred seventy-one thousand, nine hundred forty-five".