2520957781 has 4 divisors (see below), whose sum is σ = 2524649472. Its totient is φ = 2517266092.

The previous prime is 2520957767. The next prime is 2520957787. The reversal of 2520957781 is 1877590252.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2520957781 - 2⁵ = 2520957749 is a prime.

It is a super-2 number, since 2×2520957781² = 12710456267168887922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2520957787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1844821 + ... + 1846186.

It is an arithmetic number, because the mean of its divisors is an integer number (631162368).

Almost surely, 2^2520957781 is an apocalyptic number.

It is an amenable number.

2520957781 is a deficient number, since it is larger than the sum of its proper divisors (3691691).

2520957781 is an equidigital number, since it uses as much as digits as its factorization.

2520957781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3691690.

The product of its (nonzero) digits is 352800, while the sum is 46.

The square root of 2520957781 is about 50209.1404128770. The cubic root of 2520957781 is about 1360.9908042675.

The spelling of 2520957781 in words is "two billion, five hundred twenty million, nine hundred fifty-seven thousand, seven hundred eighty-one".