19971901 has 4 divisors (see below), whose sum is σ = 20094592. Its totient is φ = 19849212.

The previous prime is 19971899. The next prime is 19971943. The reversal of 19971901 is 10917991.

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, and also an emirpimes, since its reverse is a distinct semiprime: 10917991 = 7 ⋅1559713.

It is a cyclic number.

It is not a de Polignac number, because 19971901 - 2¹ = 19971899 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 (19971101) 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, 61101 + ... + 61426.

It is an arithmetic number, because the mean of its divisors is an integer number (5023648).

Almost surely, 2^19971901 is an apocalyptic number.

It is an amenable number.

19971901 is a deficient number, since it is larger than the sum of its proper divisors (122691).

19971901 is a wasteful number, since it uses less digits than its factorization.

19971901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122690.

The product of its (nonzero) digits is 5103, while the sum is 37.

The square root of 19971901 is about 4468.9932870838. The cubic root of 19971901 is about 271.3145813792.

The spelling of 19971901 in words is "nineteen million, nine hundred seventy-one thousand, nine hundred one".