21025145 has 16 divisors (see below), whose sum is σ = 26429760. Its totient is φ = 16035264.

The previous prime is 21025129. The next prime is 21025157. The reversal of 21025145 is 54152012.

It is a cyclic number.

It is not a de Polignac number, because 21025145 - 2⁴ = 21025129 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11162 + ... + 12908.

It is an arithmetic number, because the mean of its divisors is an integer number (1651860).

Almost surely, 2^21025145 is an apocalyptic number.

It is an amenable number.

21025145 is a deficient number, since it is larger than the sum of its proper divisors (5404615).

21025145 is a wasteful number, since it uses less digits than its factorization.

21025145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1864.

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

The square root of 21025145 is about 4585.3184186052. The cubic root of 21025145 is about 276.0024898256.

Adding to 21025145 its reverse (54152012), we get a palindrome (75177157).

It can be divided in two parts, 21025 and 145, that multiplied together give a cube (3048625 = 145³).

The spelling of 21025145 in words is "twenty-one million, twenty-five thousand, one hundred forty-five".