21553001 has 8 divisors (see below), whose sum is σ = 22632000. Its totient is φ = 20485872.

The previous prime is 21552983. The next prime is 21553009. The reversal of 21553001 is 10035512.

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 21553001 - 2²² = 17358697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21553009) 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, 875 + ... + 6623.

It is an arithmetic number, because the mean of its divisors is an integer number (2829000).

Almost surely, 2^21553001 is an apocalyptic number.

It is an amenable number.

21553001 is a deficient number, since it is larger than the sum of its proper divisors (1078999).

21553001 is a wasteful number, since it uses less digits than its factorization.

21553001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5935.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 21553001 is about 4642.5209746430. The cubic root of 21553001 is about 278.2931925650.

Adding to 21553001 its reverse (10035512), we get a palindrome (31588513).

The spelling of 21553001 in words is "twenty-one million, five hundred fifty-three thousand, one".