21520501 has 8 divisors (see below), whose sum is σ = 22074624. Its totient is φ = 20970480.

The previous prime is 21520493. The next prime is 21520507. The reversal of 21520501 is 10502512.

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 21520501 - 2³ = 21520493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520507) 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, 11491 + ... + 13231.

It is an arithmetic number, because the mean of its divisors is an integer number (2759328).

Almost surely, 2^21520501 is an apocalyptic number.

It is an amenable number.

21520501 is a deficient number, since it is larger than the sum of its proper divisors (554123).

21520501 is a wasteful number, since it uses less digits than its factorization.

21520501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2051.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 21520501 is about 4639.0194006923. The cubic root of 21520501 is about 278.1532417730.

The spelling of 21520501 in words is "twenty-one million, five hundred twenty thousand, five hundred one".