21764151 has 12 divisors (see below), whose sum is σ = 31543512. Its totient is φ = 14460336.

The previous prime is 21764143. The next prime is 21764179. The reversal of 21764151 is 15146712.

It is a happy number.

21764151 is a `hidden beast` number, since 2 + 17 + 641 + 5 + 1 = 666.

It is not a de Polignac number, because 21764151 - 2³ = 21764143 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21764111) 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 11 ways as a sum of consecutive naturals, for example, 1176 + ... + 6701.

It is an arithmetic number, because the mean of its divisors is an integer number (2628626).

Almost surely, 2^21764151 is an apocalyptic number.

21764151 is a deficient number, since it is larger than the sum of its proper divisors (9779361).

21764151 is a wasteful number, since it uses less digits than its factorization.

21764151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8190 (or 8187 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 21764151 is about 4665.2064263010. The cubic root of 21764151 is about 279.1990332216.

The spelling of 21764151 in words is "twenty-one million, seven hundred sixty-four thousand, one hundred fifty-one".