21740386 has 16 divisors (see below), whose sum is σ = 33878520. Its totient is φ = 10454400.

The previous prime is 21740371. The next prime is 21740387. The reversal of 21740386 is 68304712.

It can be written as a sum of positive squares in 4 ways, for example, as 16966161 + 4774225 = 4119^2 + 2185^2 .

It is not an unprimeable number, because it can be changed into a prime (21740387) 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, 4936 + ... + 8236.

Almost surely, 2^21740386 is an apocalyptic number.

21740386 is a deficient number, since it is larger than the sum of its proper divisors (12138134).

21740386 is a wasteful number, since it uses less digits than its factorization.

21740386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3429.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 21740386 is about 4662.6586836268. The cubic root of 21740386 is about 279.0973739756.

The spelling of 21740386 in words is "twenty-one million, seven hundred forty thousand, three hundred eighty-six".