21434651 has 4 divisors (see below), whose sum is σ = 24496752. Its totient is φ = 18372552.

The previous prime is 21434639. The next prime is 21434657. The reversal of 21434651 is 15643412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21434651 - 2⁶ = 21434587 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21434651.

It is not an unprimeable number, because it can be changed into a prime (21434657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1531040 + ... + 1531053.

It is an arithmetic number, because the mean of its divisors is an integer number (6124188).

Almost surely, 2^21434651 is an apocalyptic number.

21434651 is a deficient number, since it is larger than the sum of its proper divisors (3062101).

21434651 is an equidigital number, since it uses as much as digits as its factorization.

21434651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3062100.

The product of its digits is 2880, while the sum is 26.

The square root of 21434651 is about 4629.7571210594. The cubic root of 21434651 is about 277.7828774116.

The spelling of 21434651 in words is "twenty-one million, four hundred thirty-four thousand, six hundred fifty-one".