25021228761 has 9 divisors (see below), whose sum is σ = 36142460341. Its totient is φ = 16680502812.

The previous prime is 25021228759. The next prime is 25021228789. The reversal of 25021228761 is 16782212052.

It is a happy number.

The square root of 25021228761 is 158181.

It is a perfect power (a square), and thus also a powerful number.

25021228761 is a `hidden beast` number, since 2 + 502 + 12 + 2 + 87 + 61 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 25021228761 - 2¹ = 25021228759 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25021228751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 448180 + ... + 500906.

Almost surely, 2^25021228761 is an apocalyptic number.

25021228761 is the 158181-st square number.

25021228761 is the 79091-st centered octagonal number.

It is an amenable number.

25021228761 is a deficient number, since it is larger than the sum of its proper divisors (11121231580).

25021228761 is an frugal number, since it uses more digits than its factorization.

25021228761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105460 (or 52730 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

Multiplying 25021228761 by its sum of digits (36), we get a square (900764235396 = 949086²).

The spelling of 25021228761 in words is "twenty-five billion, twenty-one million, two hundred twenty-eight thousand, seven hundred sixty-one".