21012425 has 36 divisors (see below), whose sum is σ = 32124060. Its totient is φ = 13547520.

The previous prime is 21012421. The next prime is 21012449. The reversal of 21012425 is 52421012.

It can be written as a sum of positive squares in 6 ways, for example, as 182329 + 20830096 = 427^2 + 4564^2 .

It is not a de Polignac number, because 21012425 - 2² = 21012421 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is not an unprimeable number, because it can be changed into a prime (21012421) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 20321 + ... + 21329.

It is an arithmetic number, because the mean of its divisors is an integer number (892335).

Almost surely, 2^21012425 is an apocalyptic number.

21012425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21012425 is a deficient number, since it is larger than the sum of its proper divisors (11111635).

21012425 is a wasteful number, since it uses less digits than its factorization.

21012425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050 (or 1038 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 21012425 is about 4583.9311731308. The cubic root of 21012425 is about 275.9468190261.

Adding to 21012425 its reverse (52421012), we get a palindrome (73433437).

The spelling of 21012425 in words is "twenty-one million, twelve thousand, four hundred twenty-five".