21500131 has 8 divisors (see below), whose sum is σ = 21954240. Its totient is φ = 21049128.

The previous prime is 21500111. The next prime is 21500137. The reversal of 21500131 is 13100512.

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

It is a cyclic number.

It is not a de Polignac number, because 21500131 - 2⁹ = 21499619 is a prime.

It is a super-2 number, since 2×21500131² = 924511266034322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21500137) 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, 17520 + ... + 18706.

It is an arithmetic number, because the mean of its divisors is an integer number (2744280).

Almost surely, 2^21500131 is an apocalyptic number.

21500131 is a deficient number, since it is larger than the sum of its proper divisors (454109).

21500131 is a wasteful number, since it uses less digits than its factorization.

21500131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1553.

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 21500131 is about 4636.8233738196. The cubic root of 21500131 is about 278.0654530769.

Adding to 21500131 its reverse (13100512), we get a palindrome (34600643).

The spelling of 21500131 in words is "twenty-one million, five hundred thousand, one hundred thirty-one".