21651429 has 8 divisors (see below), whose sum is σ = 29864160. Its totient is φ = 13936496.

The previous prime is 21651419. The next prime is 21651439. The reversal of 21651429 is 92415612.

It is an interprime number because it is at equal distance from previous prime (21651419) and next prime (21651439).

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

It is a cyclic number.

It is not a de Polignac number, because 21651429 - 2⁸ = 21651173 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21651396 and 21651405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21651419) 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, 124347 + ... + 124520.

It is an arithmetic number, because the mean of its divisors is an integer number (3733020).

Almost surely, 2^21651429 is an apocalyptic number.

21651429 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21651429 is a deficient number, since it is larger than the sum of its proper divisors (8212731).

21651429 is a wasteful number, since it uses less digits than its factorization.

21651429 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248899.

The product of its digits is 4320, while the sum is 30.

The square root of 21651429 is about 4653.1096054144. The cubic root of 21651429 is about 278.7161847080.

The spelling of 21651429 in words is "twenty-one million, six hundred fifty-one thousand, four hundred twenty-nine".