21774440 has 32 divisors (see below), whose sum is σ = 49670280. Its totient is φ = 8589312.

The previous prime is 21774439. The next prime is 21774443. The reversal of 21774440 is 4447712.

It can be written as a sum of positive squares in 4 ways, for example, as 16176484 + 5597956 = 4022^2 + 2366^2 .

It is not an unprimeable number, because it can be changed into a prime (21774443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 809 + ... + 6648.

Almost surely, 2^21774440 is an apocalyptic number.

21774440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21774440 is an abundant number, since it is smaller than the sum of its proper divisors (27895840).

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

21774440 is a wasteful number, since it uses less digits than its factorization.

21774440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7541 (or 7537 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 29.

The square root of 21774440 is about 4666.3090339153. The cubic root of 21774440 is about 279.2430233943.

The spelling of 21774440 in words is "twenty-one million, seven hundred seventy-four thousand, four hundred forty".