61457721 has 16 divisors (see below), whose sum is σ = 88495680. Its totient is φ = 37713600.

The previous prime is 61457719. The next prime is 61457743. The reversal of 61457721 is 12775416.

It is not a de Polignac number, because 61457721 - 2¹ = 61457719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61457821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13146 + ... + 17196.

It is an arithmetic number, because the mean of its divisors is an integer number (5530980).

Almost surely, 2^61457721 is an apocalyptic number.

It is an amenable number.

61457721 is a deficient number, since it is larger than the sum of its proper divisors (27037959).

61457721 is a wasteful number, since it uses less digits than its factorization.

61457721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4456.

The product of its digits is 11760, while the sum is 33.

The square root of 61457721 is about 7839.4974966512. The cubic root of 61457721 is about 394.6318655240.

The spelling of 61457721 in words is "sixty-one million, four hundred fifty-seven thousand, seven hundred twenty-one".