19804421 has 16 divisors (see below), whose sum is σ = 24482304. Its totient is φ = 15600384.

The previous prime is 19804417. The next prime is 19804423. The reversal of 19804421 is 12440891.

It is a cyclic number.

It is not a de Polignac number, because 19804421 - 2² = 19804417 is a prime.

It is a super-2 number, since 2×19804421² = 784430182290482, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19804423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33101 + ... + 33693.

It is an arithmetic number, because the mean of its divisors is an integer number (1530144).

Almost surely, 2^19804421 is an apocalyptic number.

It is an amenable number.

19804421 is a deficient number, since it is larger than the sum of its proper divisors (4677883).

19804421 is a wasteful number, since it uses less digits than its factorization.

With its successor (19804422) it forms an eRAP, since the sums of their prime factors are consecutive (980 and 981).

19804421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 980.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 19804421 is about 4450.2158374623. The cubic root of 19804421 is about 270.5540565942.

The spelling of 19804421 in words is "nineteen million, eight hundred four thousand, four hundred twenty-one".