21692440 has 64 divisors (see below), whose sum is σ = 60860160. Its totient is φ = 6760320.

The previous prime is 21692387. The next prime is 21692453. The reversal of 21692440 is 4429612.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 21692399 and 21692408.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 442 + ... + 6601.

It is an arithmetic number, because the mean of its divisors is an integer number (950940).

Almost surely, 2^21692440 is an apocalyptic number.

21692440 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 21692440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30430080).

21692440 is an abundant number, since it is smaller than the sum of its proper divisors (39167720).

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

21692440 is a wasteful number, since it uses less digits than its factorization.

21692440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7072 (or 7068 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21692440 is about 4657.5143585393. The cubic root of 21692440 is about 278.8920502373.

The spelling of 21692440 in words is "twenty-one million, six hundred ninety-two thousand, four hundred forty".