19900720 has 40 divisors (see below), whose sum is σ = 52880544. Its totient is φ = 6822912.

The previous prime is 19900717. The next prime is 19900723. The reversal of 19900720 is 2700991.

It is an interprime number because it is at equal distance from previous prime (19900717) and next prime (19900723).

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

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (19900723) 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, 17209 + ... + 18328.

Almost surely, 2^19900720 is an apocalyptic number.

19900720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19900720 is an abundant number, since it is smaller than the sum of its proper divisors (32979824).

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

19900720 is a wasteful number, since it uses less digits than its factorization.

19900720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35557 (or 35551 counting only the distinct ones).

The product of its (nonzero) digits is 1134, while the sum is 28.

The square root of 19900720 is about 4461.0223043603. The cubic root of 19900720 is about 270.9918707819.

The spelling of 19900720 in words is "nineteen million, nine hundred thousand, seven hundred twenty".