21261429 has 24 divisors (see below), whose sum is σ = 35235200. Its totient is φ = 12102048.

The previous prime is 21261413. The next prime is 21261433. The reversal of 21261429 is 92416212.

21261429 is a `hidden beast` number, since 21 + 2 + 614 + 29 = 666.

It is not a de Polignac number, because 21261429 - 2⁴ = 21261413 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21504 + ... + 22470.

Almost surely, 2^21261429 is an apocalyptic number.

It is an amenable number.

21261429 is a deficient number, since it is larger than the sum of its proper divisors (13973771).

21261429 is a wasteful number, since it uses less digits than its factorization.

21261429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1329 (or 1326 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 21261429 is about 4611.0117111107. The cubic root of 21261429 is about 277.0325610001.

The spelling of 21261429 in words is "twenty-one million, two hundred sixty-one thousand, four hundred twenty-nine".