19987870 has 64 divisors (see below), whose sum is σ = 43425792. Its totient is φ = 6480000.

The previous prime is 19987861. The next prime is 19987879. The reversal of 19987870 is 7878991.

It is an interprime number because it is at equal distance from previous prime (19987861) and next prime (19987879).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19987879) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 132295 + ... + 132445.

It is an arithmetic number, because the mean of its divisors is an integer number (678528).

Almost surely, 2^19987870 is an apocalyptic number.

19987870 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19987870 is an abundant number, since it is smaller than the sum of its proper divisors (23437922).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19987870 is a wasteful number, since it uses less digits than its factorization.

19987870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257.

The product of its (nonzero) digits is 254016, while the sum is 49.

The square root of 19987870 is about 4470.7795740788. The cubic root of 19987870 is about 271.3868740854.

The spelling of 19987870 in words is "nineteen million, nine hundred eighty-seven thousand, eight hundred seventy".