21503480 has 16 divisors (see below), whose sum is σ = 48382920. Its totient is φ = 8601376.

The previous prime is 21503479. The next prime is 21503527. The reversal of 21503480 is 8430512.

It is a super-2 number, since 2×21503480² = 924799304220800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 268754 + ... + 268833.

Almost surely, 2^21503480 is an apocalyptic number.

21503480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21503480 is an abundant number, since it is smaller than the sum of its proper divisors (26879440).

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

21503480 is a wasteful number, since it uses less digits than its factorization.

21503480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537598 (or 537594 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21503480 is about 4637.1844906150. The cubic root of 21503480 is about 278.0798900874.

Adding to 21503480 its reverse (8430512), we get a palindrome (29933992).

The spelling of 21503480 in words is "twenty-one million, five hundred three thousand, four hundred eighty".