21051061 has 8 divisors (see below), whose sum is σ = 21401600. Its totient is φ = 20703600.

The previous prime is 21051059. The next prime is 21051091. The reversal of 21051061 is 16015012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21051061 - 2¹ = 21051059 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15820 + ... + 17098.

It is an arithmetic number, because the mean of its divisors is an integer number (2675200).

Almost surely, 2^21051061 is an apocalyptic number.

It is an amenable number.

21051061 is a deficient number, since it is larger than the sum of its proper divisors (350539).

21051061 is a wasteful number, since it uses less digits than its factorization.

21051061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1539.

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

The square root of 21051061 is about 4588.1435243462. The cubic root of 21051061 is about 276.1158452644.

Adding to 21051061 its reverse (16015012), we get a palindrome (37066073).

The spelling of 21051061 in words is "twenty-one million, fifty-one thousand, sixty-one".