21553502 has 4 divisors (see below), whose sum is σ = 32330256. Its totient is φ = 10776750.

The previous prime is 21553487. The next prime is 21553517. The reversal of 21553502 is 20535512.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21553487) and next prime (21553517).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5388374 + ... + 5388377.

It is an arithmetic number, because the mean of its divisors is an integer number (8082564).

Almost surely, 2^21553502 is an apocalyptic number.

21553502 is a deficient number, since it is larger than the sum of its proper divisors (10776754).

21553502 is a wasteful number, since it uses less digits than its factorization.

21553502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10776753.

The product of its (nonzero) digits is 1500, while the sum is 23.

The square root of 21553502 is about 4642.5749320824. The cubic root of 21553502 is about 278.2953488589.

The spelling of 21553502 in words is "twenty-one million, five hundred fifty-three thousand, five hundred two".