21011995 has 8 divisors (see below), whose sum is σ = 26310816. Its totient is φ = 16078656.

The previous prime is 21011981. The next prime is 21012053. The reversal of 21011995 is 59911012.

21011995 = T₁₆₂ + T₁₆₃ + ... + T₅₀₆.

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

It is not a de Polignac number, because 21011995 - 2¹³ = 21003803 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91242 + ... + 91471.

It is an arithmetic number, because the mean of its divisors is an integer number (3288852).

Almost surely, 2^21011995 is an apocalyptic number.

21011995 is a deficient number, since it is larger than the sum of its proper divisors (5298821).

21011995 is a wasteful number, since it uses less digits than its factorization.

21011995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182741.

The product of its (nonzero) digits is 810, while the sum is 28.

The square root of 21011995 is about 4583.8842699178. The cubic root of 21011995 is about 275.9449366804.

It can be divided in two parts, 2101 and 1995, that added together give a 12-th power (4096 = 2¹²).

The spelling of 21011995 in words is "twenty-one million, eleven thousand, nine hundred ninety-five".