21820623 has 8 divisors (see below), whose sum is σ = 31739136. Its totient is φ = 13224600.

The previous prime is 21820613. The next prime is 21820633. The reversal of 21820623 is 32602812.

It is an interprime number because it is at equal distance from previous prime (21820613) and next prime (21820633).

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

It is not a de Polignac number, because 21820623 - 2⁹ = 21820111 is a prime.

It is a super-2 number, since 2×21820623² = 952279176216258, which contains 22 as substring.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 21820593 and 21820602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21820613) 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, 330583 + ... + 330648.

It is an arithmetic number, because the mean of its divisors is an integer number (3967392).

Almost surely, 2^21820623 is an apocalyptic number.

21820623 is a deficient number, since it is larger than the sum of its proper divisors (9918513).

21820623 is a wasteful number, since it uses less digits than its factorization.

21820623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661245.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21820623 is about 4671.2549705620. The cubic root of 21820623 is about 279.4403062900.

The spelling of 21820623 in words is "twenty-one million, eight hundred twenty thousand, six hundred twenty-three".