21791340 has 36 divisors (see below), whose sum is σ = 66100944. Its totient is φ = 5810976.

The previous prime is 21791333. The next prime is 21791353. The reversal of 21791340 is 4319712.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60352 + ... + 60711.

Almost surely, 2^21791340 is an apocalyptic number.

21791340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21791340 is an abundant number, since it is smaller than the sum of its proper divisors (44309604).

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

21791340 is a wasteful number, since it uses less digits than its factorization.

21791340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121078 (or 121073 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21791340 is about 4668.1195357446. The cubic root of 21791340 is about 279.3152485461.

The spelling of 21791340 in words is "twenty-one million, seven hundred ninety-one thousand, three hundred forty".