625261981 has 2 divisors, whose sum is σ = 625261982. Its totient is φ = 625261980.

The previous prime is 625261951. The next prime is 625262047. The reversal of 625261981 is 189162526.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 435097881 + 190164100 = 20859^2 + 13790^2 .

It is a cyclic number.

It is not a de Polignac number, because 625261981 - 2¹¹ = 625259933 is a prime.

It is a super-3 number, since 3×625261981³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (625261951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 312630990 + 312630991.

It is an arithmetic number, because the mean of its divisors is an integer number (312630991).

Almost surely, 2^625261981 is an apocalyptic number.

It is an amenable number.

625261981 is a deficient number, since it is larger than the sum of its proper divisors (1).

625261981 is an equidigital number, since it uses as much as digits as its factorization.

625261981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 40.

The square root of 625261981 is about 25005.2390710427. The cubic root of 625261981 is about 855.1074183063.

The spelling of 625261981 in words is "six hundred twenty-five million, two hundred sixty-one thousand, nine hundred eighty-one".