21970023 has 16 divisors (see below), whose sum is σ = 31900800. Its totient is φ = 13396320.

The previous prime is 21970021. The next prime is 21970043. The reversal of 21970023 is 32007912.

It is not a de Polignac number, because 21970023 - 2¹ = 21970021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21969975 and 21970002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21970021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4993 + ... + 8298.

It is an arithmetic number, because the mean of its divisors is an integer number (1993800).

Almost surely, 2^21970023 is an apocalyptic number.

21970023 is a deficient number, since it is larger than the sum of its proper divisors (9930777).

21970023 is a wasteful number, since it uses less digits than its factorization.

21970023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13342.

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 21970023 is about 4687.2191115842. The cubic root of 21970023 is about 280.0766074398.

Adding to 21970023 its reverse (32007912), we get a palindrome (53977935).

The spelling of 21970023 in words is "twenty-one million, nine hundred seventy thousand, twenty-three".