19801947 has 16 divisors (see below), whose sum is σ = 28881792. Its totient is φ = 11968320.

The previous prime is 19801937. The next prime is 19801949. The reversal of 19801947 is 74910891.

It is a happy number.

It is not a de Polignac number, because 19801947 - 2⁴ = 19801931 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19801949) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17503 + ... + 18599.

It is an arithmetic number, because the mean of its divisors is an integer number (1805112).

Almost surely, 2^19801947 is an apocalyptic number.

19801947 is a deficient number, since it is larger than the sum of its proper divisors (9079845).

19801947 is a wasteful number, since it uses less digits than its factorization.

19801947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1658.

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 19801947 is about 4449.9378647347. The cubic root of 19801947 is about 270.5427901097.

The spelling of 19801947 in words is "nineteen million, eight hundred one thousand, nine hundred forty-seven".