21390354 has 12 divisors (see below), whose sum is σ = 46345806. Its totient is φ = 7130112.

The previous prime is 21390337. The next prime is 21390377. The reversal of 21390354 is 45309312.

It can be written as a sum of positive squares in only one way, i.e., 21372129 + 18225 = 4623^2 + 135^2 .

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, 594159 + ... + 594194.

Almost surely, 2^21390354 is an apocalyptic number.

21390354 is an abundant number, since it is smaller than the sum of its proper divisors (24955452).

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

21390354 is a wasteful number, since it uses less digits than its factorization.

21390354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1188361 (or 1188358 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 21390354 is about 4624.9707026099. The cubic root of 21390354 is about 277.5913894269.

Adding to 21390354 its reverse (45309312), we get a palindrome (66699666).

The spelling of 21390354 in words is "twenty-one million, three hundred ninety thousand, three hundred fifty-four".