21749590 has 16 divisors (see below), whose sum is σ = 39247488. Its totient is φ = 8678016.

The previous prime is 21749573. The next prime is 21749593. The reversal of 21749590 is 9594712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21749593) 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, 1819 + ... + 6841.

It is an arithmetic number, because the mean of its divisors is an integer number (2452968).

Almost surely, 2^21749590 is an apocalyptic number.

21749590 is a deficient number, since it is larger than the sum of its proper divisors (17497898).

21749590 is a wasteful number, since it uses less digits than its factorization.

21749590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5463.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 21749590 is about 4663.6455697233. The cubic root of 21749590 is about 279.1367545981.

The spelling of 21749590 in words is "twenty-one million, seven hundred forty-nine thousand, five hundred ninety".