61721701615 has 8 divisors (see below), whose sum is σ = 84646905120. Its totient is φ = 42323452512.

The previous prime is 61721701607. The next prime is 61721701621. The reversal of 61721701615 is 51610712716.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61721701615 - 2³ = 61721701607 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 881738560 + ... + 881738629.

It is an arithmetic number, because the mean of its divisors is an integer number (10580863140).

Almost surely, 2^61721701615 is an apocalyptic number.

61721701615 is a deficient number, since it is larger than the sum of its proper divisors (22925203505).

61721701615 is a wasteful number, since it uses less digits than its factorization.

61721701615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1763477201.

The product of its (nonzero) digits is 17640, while the sum is 37.

The spelling of 61721701615 in words is "sixty-one billion, seven hundred twenty-one million, seven hundred one thousand, six hundred fifteen".