21860851 has 4 divisors (see below), whose sum is σ = 21874104. Its totient is φ = 21847600.

The previous prime is 21860843. The next prime is 21860863. The reversal of 21860851 is 15806812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21860851 - 2³ = 21860843 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21860651) 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, 3730 + ... + 7591.

It is an arithmetic number, because the mean of its divisors is an integer number (5468526).

Almost surely, 2^21860851 is an apocalyptic number.

21860851 is a deficient number, since it is larger than the sum of its proper divisors (13253).

21860851 is a wasteful number, since it uses less digits than its factorization.

21860851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13252.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 21860851 is about 4675.5588970732. The cubic root of 21860851 is about 279.6119241157.

The spelling of 21860851 in words is "twenty-one million, eight hundred sixty thousand, eight hundred fifty-one".