21502140 has 48 divisors (see below), whose sum is σ = 65681280. Its totient is φ = 5212480.

The previous prime is 21502123. The next prime is 21502157. The reversal of 21502140 is 4120512.

It is an interprime number because it is at equal distance from previous prime (21502123) and next prime (21502157).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15630 + ... + 16949.

It is an arithmetic number, because the mean of its divisors is an integer number (1368360).

Almost surely, 2^21502140 is an apocalyptic number.

21502140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21502140 is an abundant number, since it is smaller than the sum of its proper divisors (44179140).

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

21502140 is a wasteful number, since it uses less digits than its factorization.

21502140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32602 (or 32600 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21502140 is about 4637.0400041406. The cubic root of 21502140 is about 278.0741137388.

Adding to 21502140 its reverse (4120512), we get a palindrome (25622652).

The spelling of 21502140 in words is "twenty-one million, five hundred two thousand, one hundred forty".