21727131 has 8 divisors (see below), whose sum is σ = 28992000. Its totient is φ = 14473512.

The previous prime is 21727117. The next prime is 21727183. The reversal of 21727131 is 13172712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21727131 - 2¹⁷ = 21596059 is a prime.

It is a super-2 number, since 2×21727131² = 944136442982322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21727231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4186 + ... + 7808.

It is an arithmetic number, because the mean of its divisors is an integer number (3624000).

Almost surely, 2^21727131 is an apocalyptic number.

21727131 is a deficient number, since it is larger than the sum of its proper divisors (7264869).

21727131 is a wasteful number, since it uses less digits than its factorization.

21727131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5625.

The product of its digits is 588, while the sum is 24.

The square root of 21727131 is about 4661.2370675605. The cubic root of 21727131 is about 279.0406410395.

Adding to 21727131 its reverse (13172712), we get a palindrome (34899843).

The spelling of 21727131 in words is "twenty-one million, seven hundred twenty-seven thousand, one hundred thirty-one".