19961520 has 80 divisors (see below), whose sum is σ = 63900672. Its totient is φ = 5149440.

The previous prime is 19961509. The next prime is 19961527. The reversal of 19961520 is 2516991.

It is a tau number, because it is divible by the number of its divisors (80).

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19961527) 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, 6099 + ... + 8781.

Almost surely, 2^19961520 is an apocalyptic number.

19961520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19961520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31950336).

19961520 is an abundant number, since it is smaller than the sum of its proper divisors (43939152).

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

19961520 is a wasteful number, since it uses less digits than its factorization.

19961520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2730 (or 2724 counting only the distinct ones).

The product of its (nonzero) digits is 4860, while the sum is 33.

The square root of 19961520 is about 4467.8316888621. The cubic root of 19961520 is about 271.2675652439.

The spelling of 19961520 in words is "nineteen million, nine hundred sixty-one thousand, five hundred twenty".