19871955 has 24 divisors (see below), whose sum is σ = 34564608. Its totient is φ = 10561536.

The previous prime is 19871953. The next prime is 19872001. The reversal of 19871955 is 55917891.

It is not a de Polignac number, because 19871955 - 2¹ = 19871953 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 19871955.

It is not an unprimeable number, because it can be changed into a prime (19871953) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16659 + ... + 17811.

It is an arithmetic number, because the mean of its divisors is an integer number (1440192).

Almost surely, 2^19871955 is an apocalyptic number.

19871955 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

19871955 is a deficient number, since it is larger than the sum of its proper divisors (14692653).

19871955 is a wasteful number, since it uses less digits than its factorization.

19871955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1547 (or 1544 counting only the distinct ones).

The product of its digits is 113400, while the sum is 45.

The square root of 19871955 is about 4457.7971017084. The cubic root of 19871955 is about 270.8612416737.

The spelling of 19871955 in words is "nineteen million, eight hundred seventy-one thousand, nine hundred fifty-five".