19997750 has 32 divisors (see below), whose sum is σ = 38368512. Its totient is φ = 7800000.

The previous prime is 19997743. The next prime is 19997779. The reversal of 19997750 is 5779991.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 19997695 and 19997704.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9275 + ... + 11225.

It is an arithmetic number, because the mean of its divisors is an integer number (1199016).

Almost surely, 2^19997750 is an apocalyptic number.

19997750 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19997750 is a deficient number, since it is larger than the sum of its proper divisors (18370762).

19997750 is a wasteful number, since it uses less digits than its factorization.

19997750 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2009 (or 1999 counting only the distinct ones).

The product of its (nonzero) digits is 178605, while the sum is 47.

The square root of 19997750 is about 4471.8843902767. The cubic root of 19997750 is about 271.4315822117.

The spelling of 19997750 in words is "nineteen million, nine hundred ninety-seven thousand, seven hundred fifty".