21368501 has 8 divisors (see below), whose sum is σ = 26641344. Its totient is φ = 16650720.

The previous prime is 21368497. The next prime is 21368513. The reversal of 21368501 is 10586312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21368501 - 2² = 21368497 is a prime.

It is a super-2 number, since 2×21368501² = 913225669974002, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21368531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138680 + ... + 138833.

It is an arithmetic number, because the mean of its divisors is an integer number (3330168).

Almost surely, 2^21368501 is an apocalyptic number.

It is an amenable number.

21368501 is a deficient number, since it is larger than the sum of its proper divisors (5272843).

21368501 is a wasteful number, since it uses less digits than its factorization.

21368501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277531.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 21368501 is about 4622.6075974497. The cubic root of 21368501 is about 277.4968254378.

The spelling of 21368501 in words is "twenty-one million, three hundred sixty-eight thousand, five hundred one".