19621861 has 4 divisors (see below), whose sum is σ = 22424992. Its totient is φ = 16818732.

The previous prime is 19621843. The next prime is 19621867. The reversal of 19621861 is 16812691.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 19621861 - 2⁷ = 19621733 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 (19621867) 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, 1401555 + ... + 1401568.

It is an arithmetic number, because the mean of its divisors is an integer number (5606248).

Almost surely, 2^19621861 is an apocalyptic number.

It is an amenable number.

19621861 is a deficient number, since it is larger than the sum of its proper divisors (2803131).

19621861 is an equidigital number, since it uses as much as digits as its factorization.

19621861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2803130.

The product of its digits is 5184, while the sum is 34.

The square root of 19621861 is about 4429.6569844628. The cubic root of 19621861 is about 269.7201535782.

The spelling of 19621861 in words is "nineteen million, six hundred twenty-one thousand, eight hundred sixty-one".