21980231 has 16 divisors (see below), whose sum is σ = 27988800. Its totient is φ = 16789248.

The previous prime is 21980197. The next prime is 21980243. The reversal of 21980231 is 13208912.

It is not a de Polignac number, because 21980231 - 2¹⁸ = 21718087 is a prime.

It is a super-2 number, since 2×21980231² = 966261109626722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21980231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21980281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1526 + ... + 6803.

It is an arithmetic number, because the mean of its divisors is an integer number (1749300).

Almost surely, 2^21980231 is an apocalyptic number.

21980231 is a deficient number, since it is larger than the sum of its proper divisors (6008569).

21980231 is a wasteful number, since it uses less digits than its factorization.

21980231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8378.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 21980231 is about 4688.3079037111. The cubic root of 21980231 is about 280.1199783446.

The spelling of 21980231 in words is "twenty-one million, nine hundred eighty thousand, two hundred thirty-one".