21731552 has 12 divisors (see below), whose sum is σ = 42784056.
Its totient is φ = 10865760.
The previous prime is 21731539. The next prime is 21731561. The reversal of 21731552 is 25513712.
It is a congruent number.
It is an unprimeable number.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339524 + ... + 339587.
It is an arithmetic number, because the mean of its divisors is an integer number (3565338).
Almost surely, 221731552 is an apocalyptic number.
It is an amenable number.
21731552 is a deficient number, since it is larger than the sum of its proper divisors (21052504).
21731552 is an equidigital number, since it uses as much as digits as its factorization.
21731552 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 679121 (or 679113 counting only the distinct ones).
The product of its digits is 2100, while the sum is 26.
The square root of 21731552 is about 4661.7112737706.
The cubic root of 21731552 is about 279.0595659957.
The spelling of 21731552 in words is "twenty-one million, seven hundred thirty-one thousand, five hundred fifty-two".