19990477 has 4 divisors (see below), whose sum is σ = 21528220. Its totient is φ = 18452736.

The previous prime is 19990459. The next prime is 19990499. The reversal of 19990477 is 77409991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 77409991 = 67 ⋅1155373.

It can be written as a sum of positive squares in 2 ways, for example, as 9916201 + 10074276 = 3149^2 + 3174^2 .

It is a cyclic number.

It is not a de Polignac number, because 19990477 - 2⁷ = 19990349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19990447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 768852 + ... + 768877.

It is an arithmetic number, because the mean of its divisors is an integer number (5382055).

Almost surely, 2^19990477 is an apocalyptic number.

It is an amenable number.

19990477 is a deficient number, since it is larger than the sum of its proper divisors (1537743).

19990477 is a wasteful number, since it uses less digits than its factorization.

19990477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537742.

The product of its (nonzero) digits is 142884, while the sum is 46.

The square root of 19990477 is about 4471.0711244622. The cubic root of 19990477 is about 271.3986724882.

The spelling of 19990477 in words is "nineteen million, nine hundred ninety thousand, four hundred seventy-seven".