21137952 has 96 divisors (see below), whose sum is σ = 62282304. Its totient is φ = 6220800.

The previous prime is 21137929. The next prime is 21137959. The reversal of 21137952 is 25973112.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (21137959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38802 + ... + 39342.

It is an arithmetic number, because the mean of its divisors is an integer number (648774).

Almost surely, 2^21137952 is an apocalyptic number.

21137952 is a gapful number since it is divisible by the number (22) 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 21137952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31141152).

21137952 is an abundant number, since it is smaller than the sum of its proper divisors (41144352).

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

21137952 is a wasteful number, since it uses less digits than its factorization.

21137952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602 (or 594 counting only the distinct ones).

The product of its digits is 3780, while the sum is 30.

The square root of 21137952 is about 4597.6028536619. The cubic root of 21137952 is about 276.4952251507.

The spelling of 21137952 in words is "twenty-one million, one hundred thirty-seven thousand, nine hundred fifty-two".