21314551 has 2 divisors, whose sum is σ = 21314552. Its totient is φ = 21314550.

The previous prime is 21314543. The next prime is 21314567. The reversal of 21314551 is 15541312.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21314551 - 2³ = 21314543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21354551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10657275 + 10657276.

It is an arithmetic number, because the mean of its divisors is an integer number (10657276).

Almost surely, 2^21314551 is an apocalyptic number.

21314551 is a deficient number, since it is larger than the sum of its proper divisors (1).

21314551 is an equidigital number, since it uses as much as digits as its factorization.

21314551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 600, while the sum is 22.

The square root of 21314551 is about 4616.7684585649. The cubic root of 21314551 is about 277.2630924506.

Adding to 21314551 its reverse (15541312), we get a palindrome (36855863).

The spelling of 21314551 in words is "twenty-one million, three hundred fourteen thousand, five hundred fifty-one".