21610693 has 4 divisors (see below), whose sum is σ = 23273068. Its totient is φ = 19948320.

The previous prime is 21610691. The next prime is 21610753. The reversal of 21610693 is 39601612.

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 7935489 + 13675204 = 2817^2 + 3698^2 .

It is a cyclic number.

It is not a de Polignac number, because 21610693 - 2¹ = 21610691 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21610691) 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, 831168 + ... + 831193.

It is an arithmetic number, because the mean of its divisors is an integer number (5818267).

Almost surely, 2^21610693 is an apocalyptic number.

It is an amenable number.

21610693 is a deficient number, since it is larger than the sum of its proper divisors (1662375).

21610693 is a wasteful number, since it uses less digits than its factorization.

21610693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1662374.

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

The square root of 21610693 is about 4648.7302567475. The cubic root of 21610693 is about 278.5412784626.

The spelling of 21610693 in words is "twenty-one million, six hundred ten thousand, six hundred ninety-three".