21998995 has 16 divisors (see below), whose sum is σ = 27648000. Its totient is φ = 16783200.

The previous prime is 21998993. The next prime is 21999007. The reversal of 21998995 is 59989912.

It is not a de Polignac number, because 21998995 - 2¹ = 21998993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21998993) 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, 10006 + ... + 12004.

It is an arithmetic number, because the mean of its divisors is an integer number (1728000).

Almost surely, 2^21998995 is an apocalyptic number.

21998995 is a deficient number, since it is larger than the sum of its proper divisors (5649005).

21998995 is a wasteful number, since it uses less digits than its factorization.

21998995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2106.

The product of its digits is 524880, while the sum is 52.

The square root of 21998995 is about 4690.3086252399. The cubic root of 21998995 is about 280.1996662589.

The spelling of 21998995 in words is "twenty-one million, nine hundred ninety-eight thousand, nine hundred ninety-five".