7861621554 has 12 divisors (see below), whose sum is σ = 17033513406. Its totient is φ = 2620540512.

The previous prime is 7861621499. The next prime is 7861621567. The reversal of 7861621554 is 4551261687.

7861621554 is a `hidden beast` number, since 7 + 8 + 616 + 21 + 5 + 5 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 4980830625 + 2880790929 = 70575^2 + 53673^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 218378359 + ... + 218378394.

Almost surely, 2^7861621554 is an apocalyptic number.

7861621554 is an abundant number, since it is smaller than the sum of its proper divisors (9171891852).

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

7861621554 is a wasteful number, since it uses less digits than its factorization.

7861621554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436756761 (or 436756758 counting only the distinct ones).

The product of its digits is 403200, while the sum is 45.

The square root of 7861621554 is about 88665.7857011373. The cubic root of 7861621554 is about 1988.4013282704.

The spelling of 7861621554 in words is "seven billion, eight hundred sixty-one million, six hundred twenty-one thousand, five hundred fifty-four".