21357351 has 40 divisors (see below), whose sum is σ = 33541200. Its totient is φ = 13530240.

The previous prime is 21357331. The next prime is 21357377. The reversal of 21357351 is 15375312.

It is not a de Polignac number, because 21357351 - 2¹⁰ = 21356327 is a prime.

It is a super-2 number, since 2×21357351² = 912272883474402, which contains 22 as substring.

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 (21357331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 195885 + ... + 195993.

It is an arithmetic number, because the mean of its divisors is an integer number (838530).

Almost surely, 2^21357351 is an apocalyptic number.

21357351 is a deficient number, since it is larger than the sum of its proper divisors (12183849).

21357351 is a wasteful number, since it uses less digits than its factorization.

21357351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221 (or 212 counting only the distinct ones).

The product of its digits is 3150, while the sum is 27.

The square root of 21357351 is about 4621.4014108277. The cubic root of 21357351 is about 277.4485514554.

The spelling of 21357351 in words is "twenty-one million, three hundred fifty-seven thousand, three hundred fifty-one".