19661955 has 8 divisors (see below), whose sum is σ = 31459152. Its totient is φ = 10486368.

The previous prime is 19661951. The next prime is 19661989. The reversal of 19661955 is 55916691.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 19661955 - 2² = 19661951 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19661951) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 655384 + ... + 655413.

It is an arithmetic number, because the mean of its divisors is an integer number (3932394).

Almost surely, 2^19661955 is an apocalyptic number.

19661955 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

19661955 is a deficient number, since it is larger than the sum of its proper divisors (11797197).

19661955 is a wasteful number, since it uses less digits than its factorization.

19661955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1310805.

The product of its digits is 72900, while the sum is 42.

The square root of 19661955 is about 4434.1803075653. The cubic root of 19661955 is about 269.9037379750.

The spelling of 19661955 in words is "nineteen million, six hundred sixty-one thousand, nine hundred fifty-five".