21905154 has 40 divisors (see below), whose sum is σ = 51226560. Its totient is φ = 6983064.

The previous prime is 21905137. The next prime is 21905159. The reversal of 21905154 is 45150912.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21905159) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 787 + ... + 6665.

It is an arithmetic number, because the mean of its divisors is an integer number (1280664).

Almost surely, 2^21905154 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21905154, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25613280).

21905154 is an abundant number, since it is smaller than the sum of its proper divisors (29321406).

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

21905154 is a wasteful number, since it uses less digits than its factorization.

21905154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5916 (or 5907 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 21905154 is about 4680.2942215207. The cubic root of 21905154 is about 279.8006829805.

The spelling of 21905154 in words is "twenty-one million, nine hundred five thousand, one hundred fifty-four".