21010061 has 4 divisors (see below), whose sum is σ = 21323712. Its totient is φ = 20696412.

The previous prime is 21010049. The next prime is 21010069. The reversal of 21010061 is 16001012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21010061 - 2⁶ = 21009997 is a prime.

It is a super-3 number, since 3×21010061³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010069) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 156725 + ... + 156858.

It is an arithmetic number, because the mean of its divisors is an integer number (5330928).

Almost surely, 2^21010061 is an apocalyptic number.

It is an amenable number.

21010061 is a deficient number, since it is larger than the sum of its proper divisors (313651).

21010061 is an equidigital number, since it uses as much as digits as its factorization.

21010061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313650.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21010061 is about 4583.6733086030. The cubic root of 21010061 is about 275.9364701849.

Adding to 21010061 its reverse (16001012), we get a palindrome (37011073).

The spelling of 21010061 in words is "twenty-one million, ten thousand, sixty-one".