21591829390 has 32 divisors (see below), whose sum is σ = 39539871360. Its totient is φ = 8486943264.

The previous prime is 21591829379. The next prime is 21591829397. The reversal of 21591829390 is 9392819512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21591829397) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1874589 + ... + 1886071.

It is an arithmetic number, because the mean of its divisors is an integer number (1235620980).

Almost surely, 2^21591829390 is an apocalyptic number.

21591829390 is a deficient number, since it is larger than the sum of its proper divisors (17948041970).

21591829390 is a wasteful number, since it uses less digits than its factorization.

21591829390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14736.

The product of its (nonzero) digits is 349920, while the sum is 49.

The spelling of 21591829390 in words is "twenty-one billion, five hundred ninety-one million, eight hundred twenty-nine thousand, three hundred ninety".