21510151 has 12 divisors (see below), whose sum is σ = 24665472. Its totient is φ = 18685056.

The previous prime is 21510133. The next prime is 21510157. The reversal of 21510151 is 15101512.

It is not a de Polignac number, because 21510151 - 2⁷ = 21510023 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21510157) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 871 + ... + 6616.

It is an arithmetic number, because the mean of its divisors is an integer number (2055456).

Almost surely, 2^21510151 is an apocalyptic number.

21510151 is a deficient number, since it is larger than the sum of its proper divisors (3155321).

21510151 is a wasteful number, since it uses less digits than its factorization.

21510151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7530 (or 7517 counting only the distinct ones).

The product of its (nonzero) digits is 50, while the sum is 16.

The square root of 21510151 is about 4637.9037290569. The cubic root of 21510151 is about 278.1086432497.

Adding to 21510151 its reverse (15101512), we get a palindrome (36611663).

The spelling of 21510151 in words is "twenty-one million, five hundred ten thousand, one hundred fifty-one".