61399640 has 32 divisors (see below), whose sum is σ = 145422000. Its totient is φ = 23266944.

The previous prime is 61399633. The next prime is 61399691. The reversal of 61399640 is 4699316.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a junction number, because it is equal to n+sod(n) for n = 61399594 and 61399603.

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, 39635 + ... + 41154.

Almost surely, 2^61399640 is an apocalyptic number.

It is an amenable number.

61399640 is an abundant number, since it is smaller than the sum of its proper divisors (84022360).

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

61399640 is a wasteful number, since it uses less digits than its factorization.

61399640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80819 (or 80815 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 38.

The square root of 61399640 is about 7835.7922381850. The cubic root of 61399640 is about 394.5075099116.

The spelling of 61399640 in words is "sixty-one million, three hundred ninety-nine thousand, six hundred forty".