21061693 has 2 divisors, whose sum is σ = 21061694. Its totient is φ = 21061692.

The previous prime is 21061673. The next prime is 21061717. The reversal of 21061693 is 39616012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13344409 + 7717284 = 3653^2 + 2778^2 .

It is a cyclic number.

It is not a de Polignac number, because 21061693 - 2²¹ = 18964541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21061603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10530846 + 10530847.

It is an arithmetic number, because the mean of its divisors is an integer number (10530847).

Almost surely, 2^21061693 is an apocalyptic number.

It is an amenable number.

21061693 is a deficient number, since it is larger than the sum of its proper divisors (1).

21061693 is an equidigital number, since it uses as much as digits as its factorization.

21061693 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 21061693 is about 4589.3020166470. The cubic root of 21061693 is about 276.1623222500.

The spelling of 21061693 in words is "twenty-one million, sixty-one thousand, six hundred ninety-three".