1971649 has 8 divisors (see below), whose sum is σ = 2126880. Its totient is φ = 1821600.

The previous prime is 1971647. The next prime is 1971659. The reversal of 1971649 is 9461791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1971649 - 2¹ = 1971647 is a prime.

It is a Duffinian number.

1971649 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1971647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 487 + ... + 2044.

It is an arithmetic number, because the mean of its divisors is an integer number (265860).

2^1971649 is an apocalyptic number.

1971649 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1971649 is a deficient number, since it is larger than the sum of its proper divisors (155231).

1971649 is a wasteful number, since it uses less digits than its factorization.

1971649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2591.

The product of its digits is 13608, while the sum is 37.

The square root of 1971649 is about 1404.1541938121. The cubic root of 1971649 is about 125.3939358787.

The spelling of 1971649 in words is "one million, nine hundred seventy-one thousand, six hundred forty-nine".