21368151 has 32 divisors (see below), whose sum is σ = 36449280. Its totient is φ = 12119328.

The previous prime is 21368107. The next prime is 21368153. The reversal of 21368151 is 15186312.

It is not a de Polignac number, because 21368151 - 2¹⁰ = 21367127 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21368153) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31225 + ... + 31901.

It is an arithmetic number, because the mean of its divisors is an integer number (1139040).

Almost surely, 2^21368151 is an apocalyptic number.

21368151 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21368151 is a deficient number, since it is larger than the sum of its proper divisors (15081129).

21368151 is a wasteful number, since it uses less digits than its factorization.

21368151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860 (or 854 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 21368151 is about 4622.5697398741. The cubic root of 21368151 is about 277.4953103663.

The spelling of 21368151 in words is "twenty-one million, three hundred sixty-eight thousand, one hundred fifty-one".