21520050 has 24 divisors (see below), whose sum is σ = 53370096. Its totient is φ = 5738640.

The previous prime is 21520021. The next prime is 21520061. The reversal of 21520050 is 5002512.

It is a super-2 number, since 2×21520050² = 926225104005000, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 71584 + ... + 71883.

It is an arithmetic number, because the mean of its divisors is an integer number (2223754).

Almost surely, 2^21520050 is an apocalyptic number.

21520050 is an abundant number, since it is smaller than the sum of its proper divisors (31850046).

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

21520050 is a wasteful number, since it uses less digits than its factorization.

21520050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143482 (or 143477 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 15.

The square root of 21520050 is about 4638.9707910268. The cubic root of 21520050 is about 278.1512986957.

Adding to 21520050 its reverse (5002512), we get a palindrome (26522562).

The spelling of 21520050 in words is "twenty-one million, five hundred twenty thousand, fifty".