21151005 has 16 divisors (see below), whose sum is σ = 35009280. Its totient is φ = 10891328.

The previous prime is 21150991. The next prime is 21151027. The reversal of 21151005 is 50015112.

It is a cyclic number.

It is not a de Polignac number, because 21151005 - 2⁴ = 21150989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23877 + ... + 24746.

It is an arithmetic number, because the mean of its divisors is an integer number (2188080).

Almost surely, 2^21151005 is an apocalyptic number.

It is an amenable number.

21151005 is a deficient number, since it is larger than the sum of its proper divisors (13858275).

21151005 is a wasteful number, since it uses less digits than its factorization.

21151005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48660.

The product of its (nonzero) digits is 50, while the sum is 15.

The square root of 21151005 is about 4599.0221786810. The cubic root of 21151005 is about 276.5521267455.

Adding to 21151005 its reverse (50015112), we get a palindrome (71166117).

The spelling of 21151005 in words is "twenty-one million, one hundred fifty-one thousand, five".