21994340 has 12 divisors (see below), whose sum is σ = 46188156. Its totient is φ = 8797728.

The previous prime is 21994333. The next prime is 21994363. The reversal of 21994340 is 4349912.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 5866084 + 16128256 = 2422^2 + 4016^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21994297 and 21994306.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 549839 + ... + 549878.

It is an arithmetic number, because the mean of its divisors is an integer number (3849013).

Almost surely, 2^21994340 is an apocalyptic number.

21994340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21994340 is an abundant number, since it is smaller than the sum of its proper divisors (24193816).

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

21994340 is a wasteful number, since it uses less digits than its factorization.

21994340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1099726 (or 1099724 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 21994340 is about 4689.8123629843. The cubic root of 21994340 is about 280.1799013945.

The spelling of 21994340 in words is "twenty-one million, nine hundred ninety-four thousand, three hundred forty".