19720240 has 40 divisors (see below), whose sum is σ = 46724688. Its totient is φ = 7737600.

The previous prime is 19720237. The next prime is 19720241. The reversal of 19720240 is 4202791.

19720240 = T₁₈₁ + T₁₈₂ + ... + T₄₉₈.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (19720241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1915 + ... + 6565.

Almost surely, 2^19720240 is an apocalyptic number.

19720240 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 19720240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23362344).

19720240 is an abundant number, since it is smaller than the sum of its proper divisors (27004448).

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

19720240 is a wasteful number, since it uses less digits than its factorization.

19720240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4717 (or 4711 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 19720240 is about 4440.7476847936. The cubic root of 19720240 is about 270.1701716451.

The spelling of 19720240 in words is "nineteen million, seven hundred twenty thousand, two hundred forty".