21864077 has 4 divisors (see below), whose sum is σ = 22455036. Its totient is φ = 21273120.

The previous prime is 21864061. The next prime is 21864097. The reversal of 21864077 is 77046812.

It is a happy number.

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 20241001 + 1623076 = 4499^2 + 1274^2 .

It is a cyclic number.

It is not a de Polignac number, because 21864077 - 2⁴ = 21864061 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 (21864097) 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, 295424 + ... + 295497.

It is an arithmetic number, because the mean of its divisors is an integer number (5613759).

Almost surely, 2^21864077 is an apocalyptic number.

It is an amenable number.

21864077 is a deficient number, since it is larger than the sum of its proper divisors (590959).

21864077 is an equidigital number, since it uses as much as digits as its factorization.

21864077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590958.

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 21864077 is about 4675.9038698416. The cubic root of 21864077 is about 279.6256775251.

The spelling of 21864077 in words is "twenty-one million, eight hundred sixty-four thousand, seventy-seven".