21053078 has 4 divisors (see below), whose sum is σ = 31579620. Its totient is φ = 10526538.

The previous prime is 21053077. The next prime is 21053093. The reversal of 21053078 is 87035012.

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 (21053077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5263268 + ... + 5263271.

It is an arithmetic number, because the mean of its divisors is an integer number (7894905).

Almost surely, 2^21053078 is an apocalyptic number.

21053078 is a deficient number, since it is larger than the sum of its proper divisors (10526542).

21053078 is a wasteful number, since it uses less digits than its factorization.

21053078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10526541.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21053078 is about 4588.3633247597. The cubic root of 21053078 is about 276.1246636303.

The spelling of 21053078 in words is "twenty-one million, fifty-three thousand, seventy-eight".