21070061 has 4 divisors (see below), whose sum is σ = 21162300. Its totient is φ = 20977824.

The previous prime is 21070033. The next prime is 21070073. The reversal of 21070061 is 16007012.

21070061 = T₄₄ + T₄₅ + ... + T₅₀₁.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14969161 + 6100900 = 3869^2 + 2470^2 .

It is a cyclic number.

It is not a de Polignac number, because 21070061 - 2²² = 16875757 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21070081) 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, 45776 + ... + 46233.

It is an arithmetic number, because the mean of its divisors is an integer number (5290575).

Almost surely, 2^21070061 is an apocalyptic number.

It is an amenable number.

21070061 is a deficient number, since it is larger than the sum of its proper divisors (92239).

21070061 is an equidigital number, since it uses as much as digits as its factorization.

21070061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92238.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21070061 is about 4590.2136115872. The cubic root of 21070061 is about 276.1988913319.

Adding to 21070061 its reverse (16007012), we get a palindrome (37077073).

The spelling of 21070061 in words is "twenty-one million, seventy thousand, sixty-one".