61620991 has 8 divisors (see below), whose sum is σ = 63273168. Its totient is φ = 59976000.

The previous prime is 61620989. The next prime is 61621003. The reversal of 61620991 is 19902616.

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 61620991 - 2¹ = 61620989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61620931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18601 + ... + 21661.

It is an arithmetic number, because the mean of its divisors is an integer number (7909146).

Almost surely, 2^61620991 is an apocalyptic number.

61620991 is a deficient number, since it is larger than the sum of its proper divisors (1652177).

61620991 is a wasteful number, since it uses less digits than its factorization.

61620991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3593.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 61620991 is about 7849.9038847619. The cubic root of 61620991 is about 394.9810192236.

The spelling of 61620991 in words is "sixty-one million, six hundred twenty thousand, nine hundred ninety-one".