21954240 has 420 divisors, whose sum is σ = 98102928. Its totient is φ = 4561920.

The previous prime is 21954227. The next prime is 21954241. The reversal of 21954240 is 4245912.

It is a tau number, because it is divible by the number of its divisors (420).

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 (21954241) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1995835 + ... + 1995845.

Almost surely, 2^21954240 is an apocalyptic number.

21954240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21954240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49051464).

21954240 is an abundant number, since it is smaller than the sum of its proper divisors (76148688).

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

21954240 is a wasteful number, since it uses less digits than its factorization.

21954240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58 (or 28 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 21954240 is about 4685.5351882149. The cubic root of 21954240 is about 280.0095234856.

The spelling of 21954240 in words is "twenty-one million, nine hundred fifty-four thousand, two hundred forty".