21851653 has 16 divisors (see below), whose sum is σ = 23745600. Its totient is φ = 20044800.

The previous prime is 21851629. The next prime is 21851657. The reversal of 21851653 is 35615812.

It is a cyclic number.

It is not a de Polignac number, because 21851653 - 2¹³ = 21843461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21851657) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 113125 + ... + 113317.

It is an arithmetic number, because the mean of its divisors is an integer number (1484100).

Almost surely, 2^21851653 is an apocalyptic number.

It is an amenable number.

21851653 is a deficient number, since it is larger than the sum of its proper divisors (1893947).

21851653 is a wasteful number, since it uses less digits than its factorization.

21851653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372.

The product of its digits is 7200, while the sum is 31.

The square root of 21851653 is about 4674.5751678629. The cubic root of 21851653 is about 279.5727028419.

The spelling of 21851653 in words is "twenty-one million, eight hundred fifty-one thousand, six hundred fifty-three".