25278216628 has 54 divisors (see below), whose sum is σ = 52878339234. Its totient is φ = 10535077728.

The previous prime is 25278216617. The next prime is 25278216653. The reversal of 25278216628 is 82661287252.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 24595021584 + 683195044 = 156828^2 + 26138^2 .

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 13538551 + ... + 13540417.

Almost surely, 2^25278216628 is an apocalyptic number.

25278216628 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25278216628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26439169617).

25278216628 is an abundant number, since it is smaller than the sum of its proper divisors (27600122606).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25278216628 is an equidigital number, since it uses as much as digits as its factorization.

25278216628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3789 (or 1913 counting only the distinct ones).

The product of its digits is 1290240, while the sum is 49.

The spelling of 25278216628 in words is "twenty-five billion, two hundred seventy-eight million, two hundred sixteen thousand, six hundred twenty-eight".