19764990 has 96 divisors (see below), whose sum is σ = 59417280. Its totient is φ = 4465152.

The previous prime is 19764989. The next prime is 19765013. The reversal of 19764990 is 9946791.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 86196 + ... + 86424.

It is an arithmetic number, because the mean of its divisors is an integer number (618930).

Almost surely, 2^19764990 is an apocalyptic number.

19764990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 19764990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29708640).

19764990 is an abundant number, since it is smaller than the sum of its proper divisors (39652290).

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

19764990 is a wasteful number, since it uses less digits than its factorization.

19764990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 386 (or 383 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The square root of 19764990 is about 4445.7833955333. The cubic root of 19764990 is about 270.3743777731.

The spelling of 19764990 in words is "nineteen million, seven hundred sixty-four thousand, nine hundred ninety".