21634051 has 2 divisors, whose sum is σ = 21634052. Its totient is φ = 21634050.

The previous prime is 21634043. The next prime is 21634073. The reversal of 21634051 is 15043612.

It is an a-pointer prime, because the next prime (21634073) can be obtained adding 21634051 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21634051 - 2³ = 21634043 is a prime.

It is not a weakly prime, because it can be changed into another prime (21634021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10817025 + 10817026.

It is an arithmetic number, because the mean of its divisors is an integer number (10817026).

Almost surely, 2^21634051 is an apocalyptic number.

21634051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21634051 is an equidigital number, since it uses as much as digits as its factorization.

21634051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21634051 is about 4651.2418771765. The cubic root of 21634051 is about 278.6415964629.

Adding to 21634051 its reverse (15043612), we get a palindrome (36677663).

The spelling of 21634051 in words is "twenty-one million, six hundred thirty-four thousand, fifty-one".