21402351 has 12 divisors (see below), whose sum is σ = 32258928. Its totient is φ = 13647744.

The previous prime is 21402331. The next prime is 21402373. The reversal of 21402351 is 15320412.

It is not a de Polignac number, because 21402351 - 2⁷ = 21402223 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402331) 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, 51490 + ... + 51903.

It is an arithmetic number, because the mean of its divisors is an integer number (2688244).

Almost surely, 2^21402351 is an apocalyptic number.

21402351 is a deficient number, since it is larger than the sum of its proper divisors (10856577).

21402351 is a wasteful number, since it uses less digits than its factorization.

21402351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103422 (or 103419 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21402351 is about 4626.2675019934. The cubic root of 21402351 is about 277.6432763895.

Adding to 21402351 its reverse (15320412), we get a palindrome (36722763).

The spelling of 21402351 in words is "twenty-one million, four hundred two thousand, three hundred fifty-one".