1621205025 has 48 divisors (see below), whose sum is σ = 3051233280. Its totient is φ = 751854400.

The previous prime is 1621204993. The next prime is 1621205029. The reversal of 1621205025 is 5205021261.

It is a happy number.

It is not a de Polignac number, because 1621205025 - 2⁵ = 1621204993 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1621204986 and 1621205004.

It is not an unprimeable number, because it can be changed into a prime (1621205029) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 23745 + ... + 61694.

It is an arithmetic number, because the mean of its divisors is an integer number (63567360).

Almost surely, 2^1621205025 is an apocalyptic number.

1621205025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1621205025 is a deficient number, since it is larger than the sum of its proper divisors (1430028255).

1621205025 is a wasteful number, since it uses less digits than its factorization.

1621205025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85486 (or 85481 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 1621205025 is about 40264.1903556994. The cubic root of 1621205025 is about 1174.7514247066.

Adding to 1621205025 its reverse (5205021261), we get a palindrome (6826226286).

The spelling of 1621205025 in words is "one billion, six hundred twenty-one million, two hundred five thousand, twenty-five".