21429308 has 24 divisors (see below), whose sum is σ = 39621120. Its totient is φ = 10125360.

The previous prime is 21429293. The next prime is 21429311. The reversal of 21429308 is 80392412.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3323 + ... + 7341.

It is an arithmetic number, because the mean of its divisors is an integer number (1650880).

Almost surely, 2^21429308 is an apocalyptic number.

It is an amenable number.

21429308 is a deficient number, since it is larger than the sum of its proper divisors (18191812).

21429308 is a wasteful number, since it uses less digits than its factorization.

21429308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4097 (or 4095 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 21429308 is about 4629.1800569863. The cubic root of 21429308 is about 277.7597945810.

It can be divided in two parts, 2142930 and 8, that multiplied together give a triangular number (17143440 = T₅₈₅₅).

The spelling of 21429308 in words is "twenty-one million, four hundred twenty-nine thousand, three hundred eight".