21023154 has 12 divisors (see below), whose sum is σ = 45550206. Its totient is φ = 7007712.

The previous prime is 21023143. The next prime is 21023161. The reversal of 21023154 is 45132012.

It can be written as a sum of positive squares in only one way, i.e., 13155129 + 7868025 = 3627^2 + 2805^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1167953 = 21023154 / (2 + 1 + 0 + 2 + 3 + 1 + 5 + 4).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 583959 + ... + 583994.

Almost surely, 2^21023154 is an apocalyptic number.

21023154 is an abundant number, since it is smaller than the sum of its proper divisors (24527052).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21023154 is a wasteful number, since it uses less digits than its factorization.

21023154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1167961 (or 1167958 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21023154 is about 4585.1013074958. The cubic root of 21023154 is about 275.9937774274.

Adding to 21023154 its reverse (45132012), we get a palindrome (66155166).

The spelling of 21023154 in words is "twenty-one million, twenty-three thousand, one hundred fifty-four".