19915436500 has 24 divisors (see below), whose sum is σ = 43495314408. Its totient is φ = 7966174400.

The previous prime is 19915436483. The next prime is 19915436521. The reversal of 19915436500 is 563451991.

It can be written as a sum of positive squares in 4 ways, for example, as 103184964 + 19812251536 = 10158^2 + 140756^2 .

It is a super-2 number, since 2×19915436500² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19914937 + ... + 19915936.

It is an arithmetic number, because the mean of its divisors is an integer number (1812304767).

Almost surely, 2^19915436500 is an apocalyptic number.

19915436500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19915436500 is an abundant number, since it is smaller than the sum of its proper divisors (23579877908).

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

19915436500 is a wasteful number, since it uses less digits than its factorization.

19915436500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39830892 (or 39830880 counting only the distinct ones).

The product of its (nonzero) digits is 145800, while the sum is 43.

The spelling of 19915436500 in words is "nineteen billion, nine hundred fifteen million, four hundred thirty-six thousand, five hundred".