21872355 has 8 divisors (see below), whose sum is σ = 34995792. Its totient is φ = 11665248.

The previous prime is 21872341. The next prime is 21872369. The reversal of 21872355 is 55327812.

It is an interprime number because it is at equal distance from previous prime (21872341) and next prime (21872369).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21872355 - 2¹⁰ = 21871331 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 729064 + ... + 729093.

It is an arithmetic number, because the mean of its divisors is an integer number (4374474).

Almost surely, 2^21872355 is an apocalyptic number.

21872355 is a deficient number, since it is larger than the sum of its proper divisors (13123437).

21872355 is a wasteful number, since it uses less digits than its factorization.

21872355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1458165.

The product of its digits is 16800, while the sum is 33.

The square root of 21872355 is about 4676.7889625255. The cubic root of 21872355 is about 279.6609629431.

The spelling of 21872355 in words is "twenty-one million, eight hundred seventy-two thousand, three hundred fifty-five".