21974340 has 24 divisors (see below), whose sum is σ = 61528320. Its totient is φ = 5859808.

The previous prime is 21974321. The next prime is 21974357. The reversal of 21974340 is 4347912.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21974298 and 21974307.

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, 183060 + ... + 183179.

It is an arithmetic number, because the mean of its divisors is an integer number (2563680).

Almost surely, 2^21974340 is an apocalyptic number.

21974340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21974340 is an abundant number, since it is smaller than the sum of its proper divisors (39553980).

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

21974340 is a wasteful number, since it uses less digits than its factorization.

21974340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366251 (or 366249 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 21974340 is about 4687.6795965595. The cubic root of 21974340 is about 280.0949507908.

The spelling of 21974340 in words is "twenty-one million, nine hundred seventy-four thousand, three hundred forty".