21739086 has 12 divisors (see below), whose sum is σ = 47101392. Its totient is φ = 7246356.

The previous prime is 21739049. The next prime is 21739103. The reversal of 21739086 is 68093712.

It is a self number, because there is not a number n which added to its sum of digits gives 21739086.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 603846 + ... + 603881.

It is an arithmetic number, because the mean of its divisors is an integer number (3925116).

Almost surely, 2^21739086 is an apocalyptic number.

21739086 is an abundant number, since it is smaller than the sum of its proper divisors (25362306).

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

21739086 is a wasteful number, since it uses less digits than its factorization.

21739086 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1207735 (or 1207732 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21739086 is about 4662.5192760996. The cubic root of 21739086 is about 279.0918108450.

It can be divided in two parts, 21 and 739086, that multiplied together give a triangular number (15520806 = T₅₅₇₁).

The spelling of 21739086 in words is "twenty-one million, seven hundred thirty-nine thousand, eighty-six".