21607853 has 2 divisors, whose sum is σ = 21607854. Its totient is φ = 21607852.

The previous prime is 21607849. The next prime is 21607891. The reversal of 21607853 is 35870612.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15038884 + 6568969 = 3878^2 + 2563^2 .

It is a cyclic number.

It is not a de Polignac number, because 21607853 - 2² = 21607849 is a prime.

It is a super-2 number, since 2×21607853² = 933798622539218, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21607823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10803926 + 10803927.

It is an arithmetic number, because the mean of its divisors is an integer number (10803927).

Almost surely, 2^21607853 is an apocalyptic number.

It is an amenable number.

21607853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21607853 is an equidigital number, since it uses as much as digits as its factorization.

21607853 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21607853 is about 4648.4247869574. The cubic root of 21607853 is about 278.5290762951.

The spelling of 21607853 in words is "twenty-one million, six hundred seven thousand, eight hundred fifty-three".