19910995 has 32 divisors (see below), whose sum is σ = 28038528. Its totient is φ = 13436928.

The previous prime is 19910983. The next prime is 19910999. The reversal of 19910995 is 59901991.

It is a 11-Lehmer number, since φ(19910995) divides (19910995-1)¹¹.

It is a cyclic number.

It is not a de Polignac number, because 19910995 - 2⁵ = 19910963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19910999) 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, 40642 + ... + 41128.

It is an arithmetic number, because the mean of its divisors is an integer number (876204).

Almost surely, 2^19910995 is an apocalyptic number.

19910995 is a deficient number, since it is larger than the sum of its proper divisors (8127533).

19910995 is a wasteful number, since it uses less digits than its factorization.

19910995 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559.

The product of its (nonzero) digits is 32805, while the sum is 43.

The square root of 19910995 is about 4462.1737976013. The cubic root of 19910995 is about 271.0385016307.

The spelling of 19910995 in words is "nineteen million, nine hundred ten thousand, nine hundred ninety-five".