19897453540 has 24 divisors (see below), whose sum is σ = 43132545792. Its totient is φ = 7702239840.

The previous prime is 19897453517. The next prime is 19897453553. The reversal of 19897453540 is 4535479891.

It is a happy 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, 16045714 + ... + 16046953.

It is an arithmetic number, because the mean of its divisors is an integer number (1797189408).

Almost surely, 2^19897453540 is an apocalyptic number.

19897453540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19897453540 is an abundant number, since it is smaller than the sum of its proper divisors (23235092252).

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

19897453540 is a wasteful number, since it uses less digits than its factorization.

19897453540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32092707 (or 32092705 counting only the distinct ones).

The product of its (nonzero) digits is 5443200, while the sum is 55.

The spelling of 19897453540 in words is "nineteen billion, eight hundred ninety-seven million, four hundred fifty-three thousand, five hundred forty".