21601051 has 4 divisors (see below), whose sum is σ = 22008672. Its totient is φ = 21193432.

The previous prime is 21600991. The next prime is 21601061. The reversal of 21601051 is 15010612.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21601051 - 2¹¹ = 21599003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21601061) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 203731 + ... + 203836.

It is an arithmetic number, because the mean of its divisors is an integer number (5502168).

Almost surely, 2^21601051 is an apocalyptic number.

21601051 is a deficient number, since it is larger than the sum of its proper divisors (407621).

21601051 is an equidigital number, since it uses as much as digits as its factorization.

21601051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407620.

The product of its (nonzero) digits is 60, while the sum is 16.

The square root of 21601051 is about 4647.6930836707. The cubic root of 21601051 is about 278.4998468971.

Adding to 21601051 its reverse (15010612), we get a palindrome (36611663).

The spelling of 21601051 in words is "twenty-one million, six hundred one thousand, fifty-one".