7901561 has 6 divisors (see below), whose sum is σ = 8112762. Its totient is φ = 7691280.

The previous prime is 7901539. The next prime is 7901563. The reversal of 7901561 is 1651097.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 4818025 + 3083536 = 2195^2 + 1756^2 .

It is not a de Polignac number, because 7901561 - 2¹⁴ = 7885177 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7901563) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17780 + ... + 18218.

It is an arithmetic number, because the mean of its divisors is an integer number (1352127).

Almost surely, 2^7901561 is an apocalyptic number.

It is an amenable number.

7901561 is a deficient number, since it is larger than the sum of its proper divisors (211201).

7901561 is an frugal number, since it uses more digits than its factorization.

7901561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 919 (or 480 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 29.

The square root of 7901561 is about 2810.9715402330. The cubic root of 7901561 is about 199.1762871431.

The spelling of 7901561 in words is "seven million, nine hundred one thousand, five hundred sixty-one".