19505421 has 32 divisors (see below), whose sum is σ = 31664640. Its totient is φ = 11793600.

The previous prime is 19505413. The next prime is 19505471. The reversal of 19505421 is 12450591.

It is not a de Polignac number, because 19505421 - 2³ = 19505413 is a prime.

It is a super-2 number, since 2×19505421² = 760922896774482, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19505471) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20956 + ... + 21866.

It is an arithmetic number, because the mean of its divisors is an integer number (989520).

Almost surely, 2^19505421 is an apocalyptic number.

It is an amenable number.

19505421 is a deficient number, since it is larger than the sum of its proper divisors (12159219).

19505421 is a wasteful number, since it uses less digits than its factorization.

19505421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994 (or 988 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 19505421 is about 4416.4941978904. The cubic root of 19505421 is about 269.1855705118.

The spelling of 19505421 in words is "nineteen million, five hundred five thousand, four hundred twenty-one".