21553002 has 12 divisors (see below), whose sum is σ = 46698210. Its totient is φ = 7184328.

The previous prime is 21552983. The next prime is 21553009. The reversal of 21553002 is 20035512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 13549761 + 8003241 = 3681^2 + 2829^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1197389 = 21553002 / (2 + 1 + 5 + 5 + 3 + 0 + 0 + 2).

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 5 ways as a sum of consecutive naturals, for example, 598677 + ... + 598712.

Almost surely, 2^21553002 is an apocalyptic number.

21553002 is an abundant number, since it is smaller than the sum of its proper divisors (25145208).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21553002 is a wasteful number, since it uses less digits than its factorization.

21553002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1197397 (or 1197394 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 21553002 is about 4642.5210823431. The cubic root of 21553002 is about 278.2931968690.

Adding to 21553002 its reverse (20035512), we get a palindrome (41588514).

The spelling of 21553002 in words is "twenty-one million, five hundred fifty-three thousand, two".