21860953 has 4 divisors (see below), whose sum is σ = 22020660. Its totient is φ = 21701248.

The previous prime is 21860941. The next prime is 21860977. The reversal of 21860953 is 35906812.

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 15116544 + 6744409 = 3888^2 + 2597^2 .

It is a cyclic number.

It is not a de Polignac number, because 21860953 - 2⁹ = 21860441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21860933) 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, 79648 + ... + 79921.

It is an arithmetic number, because the mean of its divisors is an integer number (5505165).

Almost surely, 2^21860953 is an apocalyptic number.

It is an amenable number.

21860953 is a deficient number, since it is larger than the sum of its proper divisors (159707).

21860953 is a wasteful number, since it uses less digits than its factorization.

21860953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159706.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 21860953 is about 4675.5698048473. The cubic root of 21860953 is about 279.6123589931.

The spelling of 21860953 in words is "twenty-one million, eight hundred sixty thousand, nine hundred fifty-three".