19971707 has 4 divisors (see below), whose sum is σ = 22824816. Its totient is φ = 17118600.

The previous prime is 19971683. The next prime is 19971739. The reversal of 19971707 is 70717991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70717991 = 227 ⋅311533.

It is a cyclic number.

It is not a de Polignac number, because 19971707 - 2⁶ = 19971643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19971607) 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, 1426544 + ... + 1426557.

It is an arithmetic number, because the mean of its divisors is an integer number (5706204).

Almost surely, 2^19971707 is an apocalyptic number.

19971707 is a deficient number, since it is larger than the sum of its proper divisors (2853109).

19971707 is an equidigital number, since it uses as much as digits as its factorization.

19971707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2853108.

The product of its (nonzero) digits is 27783, while the sum is 41.

The square root of 19971707 is about 4468.9715819190. The cubic root of 19971707 is about 271.3137028917.

The spelling of 19971707 in words is "nineteen million, nine hundred seventy-one thousand, seven hundred seven".