21722118 has 16 divisors (see below), whose sum is σ = 47393856. Its totient is φ = 6582440.

The previous prime is 21722117. The next prime is 21722119. The reversal of 21722118 is 81122712.

It is an interprime number because it is at equal distance from previous prime (21722117) and next prime (21722119).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164496 + ... + 164627.

It is an arithmetic number, because the mean of its divisors is an integer number (2962116).

Almost surely, 2^21722118 is an apocalyptic number.

21722118 is an abundant number, since it is smaller than the sum of its proper divisors (25671738).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21722118 is a wasteful number, since it uses less digits than its factorization.

21722118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329139.

The product of its digits is 448, while the sum is 24.

The square root of 21722118 is about 4660.6993037526. The cubic root of 21722118 is about 279.0191788052.

The spelling of 21722118 in words is "twenty-one million, seven hundred twenty-two thousand, one hundred eighteen".