21354406 has 16 divisors (see below), whose sum is σ = 32631984. Its totient is φ = 10478944.

The previous prime is 21354391. The next prime is 21354407. The reversal of 21354406 is 60445312.

It is a super-2 number, since 2×21354406² = 912021311225672, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354407) 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, 32376 + ... + 33028.

It is an arithmetic number, because the mean of its divisors is an integer number (2039499).

Almost surely, 2^21354406 is an apocalyptic number.

21354406 is a deficient number, since it is larger than the sum of its proper divisors (11277578).

21354406 is a wasteful number, since it uses less digits than its factorization.

21354406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 935.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 21354406 is about 4621.0827735499. The cubic root of 21354406 is about 277.4357982580.

Adding to 21354406 its reverse (60445312), we get a palindrome (81799718).

The spelling of 21354406 in words is "twenty-one million, three hundred fifty-four thousand, four hundred six".