25615201978 has 16 divisors (see below), whose sum is σ = 39788994816. Its totient is φ = 12354844320.

The previous prime is 25615201967. The next prime is 25615201991. The reversal of 25615201978 is 87910251652.

It is a super-2 number, since 2×25615201978² (a number of 22 digits) contains 22 as substring.

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, 640576 + ... + 679387.

It is an arithmetic number, because the mean of its divisors is an integer number (2486812176).

Almost surely, 2^25615201978 is an apocalyptic number.

25615201978 is a deficient number, since it is larger than the sum of its proper divisors (14173792838).

25615201978 is a wasteful number, since it uses less digits than its factorization.

25615201978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1320309.

The product of its (nonzero) digits is 302400, while the sum is 46.

The spelling of 25615201978 in words is "twenty-five billion, six hundred fifteen million, two hundred one thousand, nine hundred seventy-eight".