61351537621 has 6 divisors (see below), whose sum is σ = 67435987766. Its totient is φ = 55774125000.

The previous prime is 61351537619. The next prime is 61351537651. The reversal of 61351537621 is 12673515316.

It can be written as a sum of positive squares in only one way, i.e., 58112334225 + 3239203396 = 241065^2 + 56914^2 .

It is not a de Polignac number, because 61351537621 - 2¹ = 61351537619 is a prime.

It is a super-2 number, since 2×61351537621² (a number of 22 digits) 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 (61351537601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 253518630 + ... + 253518871.

Almost surely, 2^61351537621 is an apocalyptic number.

It is an amenable number.

61351537621 is a deficient number, since it is larger than the sum of its proper divisors (6084450145).

61351537621 is a wasteful number, since it uses less digits than its factorization.

61351537621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507037523 (or 507037512 counting only the distinct ones).

The product of its digits is 113400, while the sum is 40.

The spelling of 61351537621 in words is "sixty-one billion, three hundred fifty-one million, five hundred thirty-seven thousand, six hundred twenty-one".