21426501 has 16 divisors (see below), whose sum is σ = 30449664. Its totient is φ = 13370544.

The previous prime is 21426481. The next prime is 21426521. The reversal of 21426501 is 10562412.

It is an interprime number because it is at equal distance from previous prime (21426481) and next prime (21426521).

It is not a de Polignac number, because 21426501 - 2⁶ = 21426437 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21426521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61 + ... + 6546.

It is an arithmetic number, because the mean of its divisors is an integer number (1903104).

Almost surely, 2^21426501 is an apocalyptic number.

It is an amenable number.

21426501 is a deficient number, since it is larger than the sum of its proper divisors (9023163).

21426501 is a wasteful number, since it uses less digits than its factorization.

21426501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6680.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21426501 is about 4628.8768616156. The cubic root of 21426501 is about 277.7476662412.

Adding to 21426501 its reverse (10562412), we get a palindrome (31988913).

The spelling of 21426501 in words is "twenty-one million, four hundred twenty-six thousand, five hundred one".