21274429 has 16 divisors (see below), whose sum is σ = 25427520. Its totient is φ = 17570560.

The previous prime is 21274427. The next prime is 21274439. The reversal of 21274429 is 92447212.

It is a cyclic number.

It is not a de Polignac number, because 21274429 - 2¹ = 21274427 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21274429.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21274427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3462 + ... + 7384.

It is an arithmetic number, because the mean of its divisors is an integer number (1589220).

Almost surely, 2^21274429 is an apocalyptic number.

21274429 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21274429 is a deficient number, since it is larger than the sum of its proper divisors (4153091).

21274429 is a wasteful number, since it uses less digits than its factorization.

21274429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3980.

The product of its digits is 8064, while the sum is 31.

The square root of 21274429 is about 4612.4211646379. The cubic root of 21274429 is about 277.0890120431.

It can be divided in two parts, 2127 and 4429, that added together give a palindrome (6556).

The spelling of 21274429 in words is "twenty-one million, two hundred seventy-four thousand, four hundred twenty-nine".