21512054 has 4 divisors (see below), whose sum is σ = 32268084. Its totient is φ = 10756026.

The previous prime is 21512053. The next prime is 21512063. The reversal of 21512054 is 45021512.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21512053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5378012 + ... + 5378015.

It is an arithmetic number, because the mean of its divisors is an integer number (8067021).

Almost surely, 2^21512054 is an apocalyptic number.

21512054 is a deficient number, since it is larger than the sum of its proper divisors (10756030).

21512054 is a wasteful number, since it uses less digits than its factorization.

21512054 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10756029.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21512054 is about 4638.1088818612. The cubic root of 21512054 is about 278.1168444185.

Adding to 21512054 its reverse (45021512), we get a palindrome (66533566).

The spelling of 21512054 in words is "twenty-one million, five hundred twelve thousand, fifty-four".