21739536 has 240 divisors, whose sum is σ = 79161600. Its totient is φ = 5660928.

The previous prime is 21739517. The next prime is 21739537. The reversal of 21739536 is 63593712.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21739536.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21739537) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 275145 + ... + 275223.

It is an arithmetic number, because the mean of its divisors is an integer number (329840).

Almost surely, 2^21739536 is an apocalyptic number.

21739536 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21739536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39580800).

21739536 is an abundant number, since it is smaller than the sum of its proper divisors (57422064).

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

21739536 is a wasteful number, since it uses less digits than its factorization.

21739536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123 (or 104 counting only the distinct ones).

The product of its digits is 34020, while the sum is 36.

The square root of 21739536 is about 4662.5675330230. The cubic root of 21739536 is about 279.0937365692.

The spelling of 21739536 in words is "twenty-one million, seven hundred thirty-nine thousand, five hundred thirty-six".